isotope and nuclear chemistry division

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\A>S Alamos National laboratory is o|»Tiit«'cl hy thf t.'nivi'fsily of < alifumia f«if tin- Hc|»artiin'iil nf K - nnii< r <uiitt'i«t W-7l<t.t i;\(,:M>.

This polar-perspective view of ozone levels in theatmosphere of the southern hemisphere shows thespringtime "hole" (black, lavender, and purple) overAntarctica. Theyellowlredlgreen crescent indicatesan ozone-rich area over midlatitudes of the southernhemisphere. This map is based on data from the totalozone mapping spectrometer on board the NationalAeronautics and Space Administration's Ximbus 7satellite. Data are color coded in Dobson units, whichare proportional to column abundance of ozone in theatmosphere. (Adapted from A. S. Stolarski, in Scientific1

American 2.58 #/ 1988.)

The distribution of minerals in geological samples kelps usdiscern the evolution and processes involved in hydrotht'rmalsystems such as the one in the Sulphur Springs area of theJemez Mountains. Here, boiling hydrothermal waters producea variety of microgeaehemieal environments and provide anexcellent site for study. Sulphur oxidation leaches the soil.as is clearly visible in this photo. The most intensely alteredrocks and soil are white to pale yellow; red tones are evidentin moderately altered areas, and unaltered zones show darkbrown to black. Another effect of these geoehemieal reactionsis the absence of plant life in all altered zones.

We use lasers to produce the intense light needed fitr speetrtt-scopic studies of geochemical solutions and materials. We tunelasers to a variety of wavelengths to examine different types ofsamples. By measuring fluorescence, absorption, or Humanscattered light, we determine such characteristics as structureand concentration of the species present. The blue beam fromthis argon ion laser is used to pump a titanium-dopi'ti saphirerml (glowing red at center); it protluces another beam that canbe tuned throughout the near infrared sftectral rcgittn butcannot be seen. We have developed a unique instrument basedon this tunable near-infrared laser to da resonance Humanand laser-induced Puorescence spectroscopy in <i variety ofgem-hemieal, environmental, and materials related systems.

CoverLocated in volcanic luff on the edge of the Xevuda lest Site, Yucca Mountain is the proposed site for <i high-level nuclearwaste repository. Laboratory and field experiments are helping us determine if the area is geologically appropriate.If there were a breach in the repository, radionuclides such as plutonium could move through the grounduater systeminto the surrounding environment. To predict their behavior in such a situation, we are studying the specifiiion ofthis and other radionuctides. In the inset photograph, it is easy to identify the four oxidation states ofplutoniumin noneomplexing perchloric <uid; blue = plutonium(lll) (the numt common), lilac - (plutoniunitY), golden yellow =plutoniumi VI), and umber - plutoniumilY). The color is caused by light interacting with outer valence {-electrons.

Progren Report

UC-491turned: June 19t§

Isotope and Nuclear Chemistry DivisionAnnual Report FY 1988

October 1987—September 1988

Donald W. Barr, Division Leader

Loc Aianos Na!'Oi;ai Laboratory

Abstract

This report describes some of the major research and development programs of the Isotope andNuclear Chemistry Division during FY 1988. The report includes articles on weapons chemistry,biochemistry and nuclear medicine, geochemistry and environmental chemistry, actinide andtransition metal chemistry, materials chemistry, nuclear structure and reactions, and theINC Division facilities and laboratories.

iv teotope and Nuclear Chemistry Division Annual Report FY 1988

LA—11620-PRC o n t e n t s DE89 014361

Point of View 2

Weapons ChemistryOverview 12Radiochemistry for Weapons Diagnostics 14Thermal Ionization Mass Spectrometry 16Mass Spectrometers and Isotope Separatoi-s—Why Both? 18

Biochemistry and Nuclear MedicineOverview 22Biosynthesis of the Coenzyme Pyrroloquinoline Quinone 24Lanthanide Schiff Base Complexes as Contrast Agents for

Magnetic Resonance Imaging 26Biomedical Applications for Radioisotope Generators 28

Geochemistry and Environmental ChemistryOverview 32Thermodynamic Properties of Aqueous Solutions at

High Temperatures and Pressures 34Geochemical Measurements Suggest Widespread Circulation of

Ocean Ridge Material 36Trace-Element Variations in the Fumes of Kilauea and Mauna Loa Volcanoes 38

Actinide and Transition Metal ChemistryOverview 42Determining the Redox Reactivity of Plutonium(IV) Colloid 44Synthesis and Properties of a New Class of Synthetically Useful Precursors 46Molecular Hydrogen Coordination to Transition Metals 48

Materials ChemistryOverview 52Solution Routes to High-Temperature Ceramic Superconductors 54

,t Chemistry of Nitroalkanes and Related Molecules at High Pressure 56Synthesis of New Quasi-One-Dimensional Mixed Valence Solids 58

Nuclear Structure and ReactionsOverview 62Molybdenum-Technetium Solar Neutrino Experiment 64Using the TOFI Spectrometer to Measure Half-Lives of Exotic Nuclei 66Fission and Multifragmentation from Niobium Beam/Gold Target Collisions 68

Division Facilities and Laboratories 72Omega West Reactor 74ICON Facility 76

AppendixDivision Personnel 80Advisory Committee 83Program Funding 84Publications 87Presentations 99Division Meetings and Seminars 111References 113

Acknowledgments

Production Team:

Editor: Jody HeikenDesigner/Illustrator: Garth Tietjen

(INC-DO/IS-12)

Assistants:Janey HeadstreamOctavio Ramos

Technical Reviewers:Sec. 1 Allan OgardSec. 2 Janet Mercer-Smith and Pat UnkeferSec. 3 Robert CharlesSec. 4 Alfred SattelbergerSec. 5 Basil SwansonSec. 7 Merle Bunker

Contributors:Marty AkinJoann BrownRuth CapronLillian HinsleyCarla LoweLia MitchellValerie OritzElaine RoybalCathy Schuch

Photographer: Henry Ortega (IS-9)

Printing Coordinator: Guadalupe Archuleta (IS-9)

ii '• Isotope and Nuclear Chemistry Division Annual Report FY 1988

Overview

Point of View

Donald W. Barr

The Isotope and Nuclear Chemistry Division'sincreased involvement in environmental andgeochemistry programs reflects our growingcommitment to these 2'esearch efforts. Nationalconcern about diminishing resourses, basicenergy shortages, atmosphere and aquiferpollution, and the demand for waste disposalhas challenged us to find successful, efficient,and cost-effective methods to solve theseproblems. The multidisciplinary scientific andengineering approaches essential for dealingwith these important issues emphasize avigorous campaign to understand the processesthat have created these problems. Many of thetechnical challenges represented by these issuesrequire basic research on the complex chemistryof ecosystems—an area in which INC Division iswell qualified to make major contributions. Theresearch efforts represented by photos andillustrations on the cover and inside front coverof this annual report are an indication of ourDivision's commitment to these programs.

Readers familiar with our annual report willnotice the new, streamlined format. We hope toshowcase a selection of the Division's programsand technical accomplishments each year.

This year we occupied major new laboratoryspace. The 15,000-ft2 Advanced RadiochemistryWeapons Diagnostics Facility was completedand dedicated in May 1988. We also were ableto occupy the new 4000-ft2 Weapons DiagnosticInstrument Development Building, and con-struction began on a new wing for weaponsradiochemical diagnostics data storage andinterpretation. Another major step came whenLaboratory Senior Management assigned highpriority to a new research reactor that willreplace our aging Omega West Reactor.

With the new fiscal year, we saw changes inDivision and Group Office staff. Bruce Croweleft Group INC-7 for an assignment to the YuccaMountain Project in Las Vegas, Nevada. Wewish him well and welcome Dave Curtis andBob Charles as Group Leader and Deputy ofthe Isotope Geochemistry Group. Gary Ellersucceeded "Woody" Woodruff as Deputy GroupLeader in Group INC-4. Basil Swanson andGene Peterson joined Bruce Erdal as half-timeTechnical Coordinators for the Division; thischange reflects the current need for increasedefforts in program development. Sara Helmickalso came to the Division Office Staff asCompliance and Accountability Officer. Inthis capacity, she will use her considerableexperience to guide the Division through

myriad audits, inventories, and compliance;issues as well as safety, security, training, andquality assurance requirements.

We welcomed David Clark to the Divisionas he began his appointment as a J. RobertOppenheimer Fellow in January 1988.

This year, I particularly wish to cite ourstaff for their valued contributions to the JointVerification Experiment with the USSR con-ducted at the Nevada Test Site August 17,1988.

On a nostalgic note—in November 1988,Group INC-11 organized a 40th Anniversaryreunion of the formal Radiochemistry Group(known in previous years by such labels asCNC-11 and J-ll). Held at Fuller Lodge, it wasan opportunity for o f current staff to meet formergroup members and leaders of the radiochemistiyorganization here at Los Alamos. Our specialguests were Rod and Louise Spence, George andSatch Cowan, Jim Sattizahn, Darleane and MarvinHoffman, Carson and Kay Mark, and Bob andNancy Thorn. There were many familiar facesand the usual tall tales of scientific—andnonscientific—events of years past.

Despite the current, rather tight fiscalsituation, the vitality and vision of ourDivision's staff are a souixe of strength uponwhich to build our future. The research effortsdescribed in this report reflect well on theirskills and expertise.

Donald W. BarrDivision Leader

Isotope and Nuclear Chemistry Division Annual Report FY 1988

Overvwu

LOS ALAMOS NATIONAL LABORATORYISOTOPE AND NUCLEAR CHEMISTRY (INC) DIVISION

TECHNICALCOORDINATORS

a «. irdalE. J PetersonS. L Susnson

u DIVISION LEADERD w. Ban

OEPUTV OIWSION LEADERI AJ. Gincarz

INC-DOTJ. R. Bralnard

P. J. Unkeler

INC-4ISOTOPE AND STRUCTURAL

CHEMISTRY

Group Leaaer-R. R. Ryan

Deputy Group Levter-P. G. Bier

INC-7ISOTOPE GEOCHEMISTRV

Group Leader-D. B. Curtis

Deputy Group Leader P.. W. Charles

INC-5RESEARCH REACTOR

Group LeaOer-U. £. BunkerDeputy Group LeaftrM M. Minor

INC-11NUCLEAR AND RADIOCHEMISTRY

Group Leaoer-W. R. Daniels

Deputy Group Leader-G. F. Grisham

Deputy Group Leader tor Medical

PMimsolopes Researcti-D. C. Moody

INC Division's mission is to develop, maintain,and supply capabilities in chemistry, nuclearchemistry, geochemistry, and stable andradioactive isotopes for solution of nationalsecurity, energy, health, and environmentalproblems. The Division's four groups fosterexcellence in fundamental research.

INC Technical CoordinatorsThe INC Technical Coordinators help Divisionand Group leaders develop new programs anddirections for research. They are knowledgeableabout cui-rent programs, areas of emphsis, andthe policies of both the Laboratory and externalagencies. The Coordinators must also stayabreast of the Division's current capabilities andthe new areas being developed. They attempt tocouple INC's skills, facilities, and interests withprogram needs; facilitate interactions with

Alexander J. GancarzDeputy Division Leader

potential sponsors; and, in some cases, encourageentirely new efforts. Environmental programsoffer myriad opportunities, particularly inproblems related to waste minimization, globalchange, and restoration of the weapons complex.Materials chemistry for advanced processing andproduction of high-temperature superconductorsalso shows significant potential. The TechnicalCoordinators devote substantial effort to smallerinitiatives as well because these frequently havegreat potential for growth and represent some ofthe most intriguing scientific frontiers.

Bruce Erdal, Gene Peterson, and Basil Swanson provide assistance as the Division's Ti-chnivalCoordinators.

Isotope and Xmlear Chemistry Usrimnn Aimuul Il< /;<;/•' !•')' 7!ts

Overview

Robert R. RyanINC-4 Group Leader

INC-4 Isotope and Structural Chemistryperforms and communicates fundamentaland supporting research in chemistry to bringtogether the areas of synthesis, separation,and use of isotopic and physical methods forstudies of structure and dynamics.

David B. CurtisINC-7 Group Leader

INC-7 Isotope Geochemistry addressesimportant national scientific problems inthe fields of nuclear chemistry and geochem-istry by employing radiochemical and massspectrometric techniques. There is particularemphasis on nuclear weapons diagnosticsand related nuclear research, atmosphericand geochemical processes, and developmentof enhanced analytical and modelingcapabilities.

Merle E. BunkerINC-5 Group Leader

INC-5 Research Reactor provides reactor-based facilities and services in support ofLaboratory programs and conducts appliedand basic research in nuclear chemistry.

William R. DanielsINC-11 Group Leader


Overview

INC-11 Nuclear and Radiochemistryapplies expertise in nuclear and radiochemistryto support national needs and Laboratoryprograms, including weapons test diagnostics,radioactive waste management, nuclearmedicine research, radioisotope production,and basic research in nuclear phenomena.The Group expands and improves our humanand facilities resources to support Laboratorygoals and to seek new applications of nuclearand radiochemistry for scientific andtechnological development.

Laboratory FellowsLaboratory Fellows are appointed in recognitionof their scientific excellence as well as sustainedoutstanding contributions and exceptionalpromise for continued professional achievementwithin their area of competence. They play a keyrole in stimulating new research initiatives.

Carl Orth's principal research involves theuse of nuclear and radiochemical techniques tostudy extinction boundaries in the fossil record.The objective is to determine if the biologicalcrises were caused by hypothesized swarms ofcomets periodically entering the inner SolarSystem—some striking the Earth—or by lessexotic terrestrial processes. In earlier work,he and his coworkers in INC Division foundthe iridium anomaly at the Cretaceous/Tertiaryboundary in nearby fluvial sediments; thisdiscovery provided strong support for the

Charles J. Orth

Jerry B. Wilhelmy

Alvarez asteroid-impact hypothesis, whichwas based on a discovery of excess iridium ata similar boundary in marine rocks. Almost allthe extinction boundaries recorded in the last600 Myr are currently being examined incollaboration with about 50 paleontologists fromaround the globe. To complement this work andprovide a better database of terrestrial impactevents, melt and target rocks from suspectedimpact structures are being examined todetermine if they resulted from impacts orvolcanism. Carl also is interested in meson/nucleus interactions and stimulation of nuclearisomers to release their stored energy.

Jerry Wilhelmy's primary research hasbeen focused on the study of nuclear fissionand the investigation of heavy ion reactions.These efforts attempt to determine the limitingconditions for the existence of nuclear matter.He will continue research in the fission processby addressing the heaviest element fissionproperties and will study the effect of nucleardissipation on the time scale of fission. One ofJerry's new major areas of interest is the field ofweak interaction studies, in which he measurestotal solar neutrino fluences to determinepossible neutrino flavor oscillations and theirconsequences on neutrino masses. He continuesto be interested in applied efforts within theDivision—especially those associated withnuclear reactions and atomic and nuclear laserpossibilities.

Isotope and Nudear Chemistry Division Annual tiept>r-t ^Y

Qverviciv

Gregory J. Kubas

Greg Kubas' research centers on theactivation of small energy-related moleculessuch as SO2 and H2 on transition metalcomplexes. His long-term goal is to reduceSO2 to sulfur or sulfur-containing species byemploying metal hydride complexes, hydrogen,and other reducing agents as a possible meansof controlling emissions that produce acid rain.Greg and his coworkers developed the firsthomogeneous (solution) catalytic process forclean and rapid conversion of SO2 to sulfurand water through the use of hydrogen andan organometallic molybdenum sulfide catalyst.Originally a spinoff of these studies, Greg'sdiscovery of molecular hydrogen coordination tometals several years ago is now recognized asone of the major advances of the decade ininorganic chemistry; his work has stimulatedmuch new research worldwide. The ability ofmetals and metal complexes to bind H2 intactrather than as atomic H" represents a new typeof chemical bonding and has profound impact inenergy-related areas such as hydrogen storageand catalysis.

INC Division'*! DOT ProgramThe Division Office Technical (DOT) programprovides INC staff members with the oppor-tunity for an internal sabbatical; the conceptstresses mutual benefits to the chosenindividuals and to the Division. The DOTprogram seeks to reward those who have

exhibited exceptional scientific merit andcreatively sought new outlets for Divisioncapabilities. The Division provides financialand resource support for the appointees duringtheir tenure and contributes to their careerdevelopment through increased exposure to theLaboratory, Directorate, Division, and Groups.The appointees serve as Division spokespersonsand assist the Division by contributing theirexpertise and ideas to new technical initiativesand program development. These processesparticularly encourage frequent communicationand interaction with Division staff. DOTappointments follow regularly scheduled callsfor applications.

In the DOT's fourth year, Pat Unkeferand James Brainard, both of INC-4, sharethe DOT appointment. Their half-time DOTresearch projects are summarized here.

Pat Unkefer's half-time appointment hasbeen devoted to the first phase of developing anenvironmental initiative within the Division.This initiative is composed of two separatetechnical efforts. The first project is to developcost-effective technology for bioremediation ofexplosives contamination. The technical basisfor this effort involves identifying and charac-terizing soil microorganisms that can completelydegrade high explosives. It may be possible touse these microbes for in situ reclamation ofsoils that are contaminated with high explosivesor for on site degradation of these explosives in

Pat J. Unkefer

Isotope and Nuclear Chemistry Division Annual Report FY1988

Overview

a biological reactor. Pat's second project is todevelop cost-effective remediation schemes foractinide contamination or for process modifi-cation by using biological chelators of theactinindes. The initial technical work for thiseffort explores two strategies: (1) identificationand characterization of biological binding agentsthat can be used either to sequester actinidesfrom solutions such as process streams, orto form barriers that would halt actinidemovement in the environment; (2) the use ofbacterial siderophores—biochelators with highaffinity for iron—to increase the solubility andhence, the extraction and removal, of actinidesfrom contaminated soils. Both projects includedeveloping a base for the technology, which is anecessary prelude to obtaining outside fundingfor these initiatives. The startup phase alsoinvolves identifying users who need thistechnology and can help fund its development.This last phase, conducted in collaboration withthe Laboratory's Energy Technology andWeapons Technology program managers, hasalready identified US Air Force, Army, and NavyResearch programs and several bioremediationcompanies.

During his INC-DOT appointment, J imBrainard is working on understandingstructure/function relationships in smallpeptides. This effort emphasizes the use of high-resolution NMR and stable isotope labeling tocharacterize the structures of signal peptides inaqueous and hydrophobic environments.

James R. Brainard

Because these signal peptides are involvedin transporting and targeting many proteinsto their proper locations in cells, they play acentral role in the compartmentation andorganization of eukaryotic cells. The labelingtechniques developed are expected tosignificantly contribute to new Laboratoryefforts in the area of structural biology. Jimalso is working to increase the contributionshigh- resolution NMR can make to Division andLaboratory research programs in actinide andlanthanide coordination chemistry—particularlyto problems in waste management and chemicalprocessing and the development of improvedMRI contrast agents.

INC Division Accomplishments in FY1968INC Division comprises 228 employees. Thistotal includes 91 member scientists (76 withPhD degrees), 7 administrative staff members,49 technicians, and 15 general support staff.In 1987, we hosted 34 postdoctoral employees(4 from foreign countries), 4 J. R. Oppenheimerfellows, 1 summer teacher, 20 undergraduatestudents, and 29 graduate research assistants.In addition, there were 195 affiliates, of whom34 were scientists from foreign countries. Animportant group of these visitors composesINC Division's Advisory Committee, which' isassembled from eminent scientists in our fieldsof interest. This committee serves the veryimportant function of reviewing our plans,progress, and priorities and bringing to ourscientific staff a different perspective on thenew and most significant developments in manyareas. Membership of our Advisory Committeefor FY 1989 is listed in the Appendix of thisreport. Division seminars, also listed in theAppendix, serve as a valuable additional andcomplementary window on interesting recentprogress and ideas from both within and outsidethe Division.

Awards and RecognitionWhen Laboratory Director Sig Hecker presentedplaques for the 1988 Distinguished ServiceAwards, he recognized the efforts of two INC-4members.

John Hanners pioneered biochemicalmethods to obtain labied sugars and ammo acidsfrom living organisms. He also established

Isotope and Nuclear Chemistry Division lit port 198S

Overview

widely used methods for separating completemixtures of carbohydrates. John's influenceextends to the lives of young scientists aswell. Over the years, he has been active inLaboratory outreach programs and hassupervised numerous undergrad co-op students.

As a tech supervisor at INC-4's ICON Facility,Charles Lehman is known for having "a feel"for production processes to improve thatfacility's operation. When Laboratory andother scientific community users' demand forhigh-purity isotopes increased substantially,Charlie's dedication helped overcome equipmentfailures, personnel shortages, and nature'sinconsistencies.

David Clark, an Oppenheimer Fellow inINC-4, was the recipient of the 1988 NobelLaureate Signature Award for GraduateEducation in Chemistiy. Sponsored by theAmerican Chemical Society, the award is thehighest honor given for graduate research inchemistry in the US. David's current workinvolves the chemistry of uranium(III) and isrepresented by an article in Sec. 4 of this report.

As the foundling father of INC-Division's newAdvanced Radiochemical Weapons DiagnosticsBuilding, James Sattizahn was honored at thededication of that new facility in May. Manyyears were dovoted to planning and ensuringsupport for the building, which is designed toallow extremely sensitive measurements onminute quantities of elements. Retired now,Jim was INC-11 Group Leader for 14 years,INC Deputy Division Leader, and a 40-yearmember of the Division and its precursors. Inspeaking of the $3.7 million, 14 500 ft2 building,he said, "A building Jike this is a resource notonly for the Lab, but for the nation—it's unique."

RetirementsIn 1953, Bruce J. Dropesky joined theRadiochemistry Group (J-ll). Throughoutmost of his career he contributed his talentsto the weapons program, but he also was activein basic research. To advance his early researchin nuclear structure and reaction mechanisms,he constructed a state-of-the-art solenoidal beta-ray spectrometer. In 1964, Bruce acquired fromSweden this Laboratory's first electromagneticmass separator, which was used for the weapons

program for the next 10 years. He helped planand supervise construction of the extensivenuclear chemistry facilities at the LAMPFaccelerator, where he initiated and led theLAMPF Nuclear Chemistry Program. For overa decade, he and colleagues from Group INC-11and universities made significant contributionsto medium-energy meson and particle physics.He realized the importance of an isotopeproduction facility at the LAMPF beam stop fornuclear medicine applications and is creditedwith the inception of this important program.Bruce is remembered for his dedication toscience and his sincere and caring personality.

Francine Lawrence retired from theLaboratory in September 1988 after morethan 30 years as a chemist in INC-11 and itspredecessors. She came to Los Alamos in 1953;joining Group J-ll as a chemical technician,she worked with Charles Browne, Louise Smith,and Darleane Hoffman on the actinides,including the exciting products of the Mike shot.After a few years away from the Laboratorywhile her husband completed his doctoralstudies at Vanderbilt University, she rejoinedthe group (then J-l l) in 1960. Francinecompleted her own B.S. and later an M.S. inchemistry to become a staff member. In her longcollaboration with Darleane Hoffman, sheworked on a variety of problems, ranging fromweapons diagnostics and the production ofheavy elements to the development of nuclearengines for rocket propulsion, undergroundradionuclide migration, and nuclear wastemanagement. This work led to coauthorship onmany journal publications reporting discoveriesin areas of actinides and fission products,including the discovery of 244Pu in nature.

Shari Lermuseaux came to Group INC-11in 1978. As an experimental equipment/facilities operator, she was responsible forthe radioactive samples chemists brought tothe counting room. Shari did the scheduling,entered sample identification into the computer,used the appropriate counter to process samples,and returned the computer-analyzed data tothe chemists. This was far from an easy jobbecause we have more than 40 differentcounters/spectrometers and their electronicappurtenances in the counting room. Sharithoroughly enjoyed her work and her cheerfulpersonality will be missed.

8 Isotope and Nuclear Chemistry Division Annual Report FY ]988

Overview

Petrita Oliver, a much travelled lady, retiredfrom INC-11 in December 1987. She beganworking in the Laboratory's Project Y as aJunior Technician in 1945. After matei-nityleave, she picked up again in CMR-3, thenmoved to CMR-4 and to J-2; following a secondmaternity leave, she returned to J-2; then shewent to J-11, J-12, and CMR-1. Pat returned toJ-11 in 1953 and then moved to the new CNC-11(subsequently renamed INC-11) in 1971, whereshe remained until her retirement. Most of herwork involved weapons radiochemistry andwaste isolation. Over the years she heldpositions, variously titled "counting technician,""microanalyst," "radiochemist," and "chem techII." As a Senior Technologist, she spent her last2 years in Group INC-11 helping to developbiomedical generators in the Medical Radio-isotopes Research Program. Pat has many secretstories that would reveal interesting facts aboutsome of her coworkers in the group—if only shewould talk!

Ramon Romero joined the Laboratoryin 1968 after 8 years with Zia Company, theLaboratory's chief contractor at that time.He went to work in Group CMF-4—laterknown as CNC-4 and then JNC-4. His majorresponsibility there was fol fabricating theICON program's first large carbon monoxidedistillation column, which was used to producecarbon monoxide highly enriched in 13C. For thenext 20 years, Ramon continued as a fabricatorwith the ICON Facility, constructing many andever-larger columns for separating differentisotopes. He contributed much to this program'ssuccessful effort to reduce—by orders ofmagnitude—the cost of light stable istopes.Ramon was always known for the high quality ofhis work and his dedication to the project; he issorely missed.

We were saddened this year by the deathof long-time Los Alamos resident HelenBruington. She had worked at the Laboratorysince 1960 and was a member of (then) GroupCNC-11 from 1974 to 1980.

Isotope and Nuclear Chemistry Division Report 1988 9

Wetipons Chemistry

Overview

Radiochemistry for Weapons Diagnostics

Thermal Ionization Mass Spectrometry

Mass Spectrometers and IsotopeSeparators—Why Both?

Wer Dons C/iem istrv

Weapons Chemistry Overview

Allen E. Ogard

The Radiochemical Test Diagnostics Programrequires a significant fraction of INC-Divisionfunding and resource commitments. We not onlycontribute to yield determinations for all LosAlamos Nevada tests but also provide details ofthe physics and chemistry of nuclear explosions.Radiochemical testing of a nuclear device can beseparated into the following six activities:

Detector development and useDrillback for samplesSample preparation from test debrisSeparation of chemical elementsAnalysis of isotopesInterpretation of results

DetectorsDetectors, either as chemical elements orchemical compounds, are added to a nucleardevice being tested. When the detector materialis activated by reaction with neutrons producedduring the test, it yields isotopes that aredifferent from those of the original element.Determining the quantity of an isotope producedgives a measure of the integral neutron fluence(neutrons per square centimeter) over theneutron range to which the reaction is sensitive.A combination of results from various detectorreactions is used to interpret test results,

Useful detectors have reaction products thatare separable from the bulk of the soil sampleand extraneous activated materials; they alsohave levels of activation that are detectableabove background production, and they can bequantified by measurement of either theirnuclear decay properties or their isotopic massratios. However, the detector must not affect theperformance of the device. Americium-241 hasbeen used as a detector since 1966, and wecontinue to research other possible detectors.1

Drillback OperationFollowing an event at the Nevada Test Site,an angled postshot hole is drilled using oil-fielddrilling techniques (Fig. 1.1). The postshot holeis drilled into and through the cavity formed bythe explosion; at the base of the cavity is apuddle of solidified melted-rock that containsmost of the fission products and activation

products from the device. Personnel from GroupINC-11 and/or Group INC-7 direct the samplingefforts in the field to ensure that samples are ofthe desired quantity and composition. A side-wall sampler collects and retrieves the samplesfrom depth. Properly packaged to contain theradioactive debris, these samples are sealed inappropriately shielded shipping containers andtransported to Los Alanos.

Samples Prepared from Test DebrisSamples obtained from the postshot holeare a mixtm-e of drilling mud, melted tuffcontaining radioactive elements, and naturaltuff. We manually separate the melted andradioactive pieces from the drilling muds andunmelted tuffs and process them into solutionssuitable for separation chemistry. Becausethese raw samples are highly radioactive,most of the dissolution operations are carriedout behind shielding. Conventional wetchemistry techniques that involve heatingsamples for relatively long periods in strongacids such as hydrofluoric and perchloric yieldcompletely dissolved and homogeneous samples.

Recently, we have found that microwaveheating the acid solutions during dissolutionresults in shorter dissolution times and smallervolumes of acids being used.

Fig. 1.1. The same techniques used to drill oilwells are employed at the Nevada lest Site.

12 Isotope and Nuclear Chemistry Division Annual Report FY19S8

Weapons Clwniiatiy

Separation ChemistryThe products that result from reaction of theneutrons with the detectors during a test aregenerally far less abundent than fission andother activation products. Although we useextremely sensitive measuring techniques suchas mass spectrometry and low-level gamma-raycounting to determine their production, thesereaction products first must be concentrated andseparated from elements that could interferewith their analysis. A comprehensive document,"Collected Radiochemical and GeochemicalProcedures," contains descriptions of chemicalprocesses that we use t< purify the reactionproducts of interest before we measure them.2

After the chemical processes, the sample issometimes subjected to mass separator analysis,which separates an element into its individualisotopes, before the element is counted. Selectedseparation processes are discussed in moredetail in the three articles that follow thisoverview.

AnalysisRadioactive isotopes decay at specific rates(half-lives) through the emission of specificradiations (tx, p1", P+, etc.). By measuring theseradiations as a function of time and energy,we can identify the isotope and measure itsconcentration quantitatively or relative to otherisotopes in the chemically separated samples.

INC Division has a large number of radiation"counters" that can measure the energy andquantity of gamma rays and particles (a, p', P+)being emitted during the decay of the radio-active species. More specific information aboutthese counters can be found in Sec. 7 of thisreport. Another technique used to measure therelative concentrations of isotopes in test debrissamples involves mass spectrometers, which arediscussed in an article within this section.

Interpretation of DataRadiochemical diagnostics of weapons testsprovide the final word on certain aspects of adevice's performance. From this informationLANL designers can infer whether the deviceworked as expected or if changes should bemade in its design.

The planning and results of weapons testdiagnostics are reported at two internalclassified forums, both of which meet monthly:

the Experimental Review Group (ERG)and the Weapons Working Group (VVWG).In addition, twice a year we hold anIntel-laboratory Working Group (ILWOG)meeting with Lawrence Livermore NationalLaboratory and other organizations to reviewcurrent procedures and new techniques inradiochemical test diagnostics.

The classified summai-ies of these activitiescan be made available to properly clearedindividuals who contact Charles Miller. GroupINC-7.

Isotope and Nuclear Chemistry Division Ann ual Report FY 19SS IS

Weapons Chemistry

Radiochemistry for WeaponsDiagnostics

Moses Attrep, Jr.

INC Division has developed a level ofradiochemical expertise that is matchednowhere else in the world. This achievementis the result of INC's pioneering endeavors andits leadership in developing radiochemistry asan essential tool for nuclear weapons testsdiagnostics. As instrumental sophisticationimproved our ability to detect radioactiveemission, radiochemical separation processeswere put to severe tests and changes. In earlierdays, most radioactive samples were countedwith traditional beta and/or sodium iodidecounting systems. Our stringent chemistryrequirements allowed for little or no interferingradioactive substances in the final countingsamples. These standards and the concomitantskills necessary to carry out the techniques ofradiochemical separations are maintained inpresent day diagnostic activities.

One example of our technological developmentis the radiochemical separation and purificationof rhodium from nuclear bomb debris. Thisprocedure was developed to ensure that thefinal sample, prepared for counting in a low-level well-type Ge(Li) counter, was free fromall radioactive contaminants. The radiochemicaldemands in the rhodium analysis do not differsignificantly from the requirements of theearlier radiochemical analyses done here.Radiochemical purity is vital: extremely smallamounts of long-lived rhodium nuclides must bedetermined, and we can tolerate no interferingsubstances that might compromise that deter-mination. The Isotope and Nuclear ChemistryDivision's "Collected Radiochemical Procedures"volume describes our procedures in detail.2

The side bar on the next page shows the variouschemical steps required to produce high-qualitysamples for the radiochemical determination ofrhodium isotopes.

As more sensitive and sophisticated instru-mental techniques become available and areused to detect radionuclides, more demandingand varied radiochemistry is required to preparethese samples for analysis. The cases describedhere illustrate how different radiochemicaldemands affect sample preparation.

The first example is mass separationof the isotopes of silver for counting anddetermination. The process requires(1) radiochemical separation and purificationof silver from debris, (2) mass separation of theisotopes, and (3) counting the individual isotopesof silver. This preparation differs from that ofrhodium in that the silver isotopes arephysically separated and counted, whereasthe rhodium analysis relies upon countingtechniques alone to determine the isotopes.By using mass separation techniques, theanalyst is able to obtain the data more quicklyand with less ambiguity. In this process, wechemically separate silver from the debris byremoving it from all interfering radionuclidesand then we carefully prepare the metal for theseparation of its isotopes on the mass separator.

The key in this procedure is the preparationof a pure sample that is suitable for the massseparation. Using a combination of radio-chemistry and instrumentation technology,we have adopted a unique process that allowsus to excell in isotope determination for nuclearweapon diagnostics. Other elements that wemass separate routinely are zirconium, thulium,europium, and lutecium.

As demands increased on the diagnostic teamto determine fewer atoms with greater precisionand accuracy, it became evident that massspectrometers would play a larger role innuclear weapons radiochemical diagnostics.This could not be done, however, without theskillful preparation of ultrapure samples formass spectrometric analysis. In our analysisof plutonium, for example, totally new conceptsof sample preparation had to be developed,demanding analytical chemistry skills thatwere normally thought unattainable, so thatthe analyst could make the determination atthe levels required. When developing andimplementing this type of work, the radio-chemist must keep in mind several points:

(1) A unique chemical separation procedureis needed to provide very highseparation factors;

(2) Labware must be specially cleaned toremove "background" levels of theelement being determined;

(3) The work must be conducted in anenvironmental".., controlled area wherethe air is carefully filtered;

14 Isotope and Nuclear Chemistry Division Annual Report FY 1988

Weapons Chemistry

(4) The analyst must wear clean outergarments; and

(5) Special reagents must be obtained andchecked for any level of the elementbeing determined.

A sample being analyzed for plutoniumcontent is treated under the conditions describedabove, and we use an established radiochemicalprocedure. This procedure, requiring severaldays, produces an ultrapure sample that isdelivered to the mass spectrometrists who loadthe sample for instrumental analysis. If theradiochemistry has been done well, the isotopiccomposition can be determined properly.Because we might be analyzing extremelysmall quantities of plutonium, it is imperativethat these strict procedures be followedconscientiously and deliberately. Bothplutonium and uranium are routinely analyzedin this manner. Although the radiochemicaldemands are higher, determinations in thelower detection levels allow INC Division tolead the field in isotopic analyses.

In his Nobel Prize acceptance speech,W. F. Libby referred to low-level radiochemicalseparation science as

"something like the discipline ofsurgery—cleanliness, care,seriousness, and practice."

The skills required and developed in INC'sweapons diagnostics program have served asa basis for pioneer work in the areas of environ-mental radiochemistry, isotope geology, andnuclear medicine.

Radiochemical Analysis for Rhodium in Debris

10-80 g Dissolved Dirt

Volume taken to 20 ml/g.Add Rh carrier and make 6H HC1.Heat to boiling and add 1-2 g Nal.Continue heating 1 b; centrifuge.Wash Rhl3 precipitate with 3M HC1.

Rhodium ChlorideAdd 35f NaCN; heat until solution occurs;add Te(IV) holdback carrier and HC1; destroyiodine by adding NaNO2. Dilute andscavenge with ferric hydroxide by makingbasic with ammonia.

Solution of [Rh(CN)6]3-

Add bariuim and precipitate with sodiumcarbonate; centrifuge.

Solution of [Rh(CN)6]3-Acidify and add Te(III) and SbdII) holdbackcarriers; precipitate sulfides with H2S; filter.

Solution of [Rh(CN)6]3"

Remove H2S by boiling; acidify and addCu(II) to form precipitate.

Cu3[Rh (CN)6]2 PrecipitatePut rhodocyano complex into solution byadding strong NaOH.

Solution of [Rh(CN)6]3-Evaporate to near dryness; add cone H2SO.|;fume.

Solution of Rh(III)Repeat Rhl3 precipitation; form cyanidecomplex; perform Fe(OH)3 scavenge, BaCO3precipitate, H2S cavenge and Cuprecipitation/dissolution; Repeat BaCo3precipitate, H2S scavenge, Cu precipitation,dissolution, and cyanide destruction.

Solution of Rh(III)Fume with HC1O4 and HNO3; neutralise withNaOH to form Rh(OH)3; centrifuge, wash,dissolve with minimum HC1, evaporate todryness, dissolve in water and transfer tocounting vial.

|

Isotope and Nuclear Chemistry Division Annual. Report FY 19SS 15

Weapons Chemistry

Thermal-Ionization Mass Spectrometry

Richard E. Perrin, Donald J. Rokop,John H. Cappis, Michael T. Murrell,Joseph C. Banar, Eddie L. Rios,Ruben D. Aguilar, and Jose A. Olivares

During the past 11 years, thermal-ionizationmass spectrometry has become an increasinglyimportant technique for the radiochemicaldiagnostics program. This technique is used inseveral ways.

• Pre- and postshot isotopic analysis ofuranium and plutonium provides theisotopic inventory data that allows usto calculate fission yields.

• Postshot analysis for specific isotopesincorporated into the test deviceprovides valuable information ongeometric and chemical fractionation.

• Analysis of long-lived isotopes formedby the interaction of neutrons withelemental tracers, which arc added tothe test device, provides additionalinformation concerning neutron fluenceand energy.

At this time, we routinely performed high-accuracy, high-sensitivity isotopic analysesfor uranium, plutonium, americium, andneptunium. Other actinides such asprotactinium and curium are analyzedwhen necessary. We can accomplish preciseisotopic analysis (better than 0.1% at the 95%confidence limit) for major ratios by using aslittle as 1 x 10"9 g of the element. In addition,for elements added as neutron monitors, wecan detect the neutron induced isotopes inconcentrations as low as 1 in 108 (relative tosoil background).

To achieve the results described above,a number of new techniques and specialinstrumental modifications have been necessary.These developments improve one or more ofthree critical performance factors: accuracy,sensitivity, and dynamic measurement range.

The first area that required significantimprovement was separations chemistry.To achieve the sensitivity and accuracy required,

separations chemistry must produce an isotopein high yield while eliminating all othercomponents that might interfere by (1) reducingionization efficiency or (2) producing isobaricinterferences in the mass range of interest.We require separation factors as high as 1012;for details of our progress in separationschemistry, see Chamberlin's article "MassSpectrometers and Isotope Separation—WhyBoth?" in this section.

The second improvement was reduction of thechemical blank, which has been accomplished bythree primary efforts. We now conduct chemicalprocessing in class 100 clean room facilities toreduce pai*ticulate blanks. We have developedsuppliers and/or in-house techniques forproducing ultrapure acids and selecting processcontainers. Microprocessing techniques havebeen applied to all separations processes toreduce the total exposure of the sample tocontamination sources. With this combinedapproach we have reduced the actinide blankto below 1 x lO 1 2 g for routine processing andto as low as 5 x 105 atoms in some specialapplications.

The final area that required majorimprovement was mass spectrometerperformance, where three components ofinstrument performance have been enhancedsubstantially. These are the detector systems,ionization processes, and abundance sensitivity.

Initially, we added pulse-counting detectors togive us the capability of detecting individualions. Combination detectors were then addedthat allow us to measure dynamic ranges ashigh as 1012. We now are investigating verylow noise detector systems to further increasedetection limits.

Ionization efficiency has improved throughthe development of several procedures.

(1) An electrodeposition system permitshigh-yield deposition of the sample,and we have successfully used furtherelectrodeposition of a diffusion barrierof platinum for all actinide analyses.This process increases the ionizationefficiency for actinides by a factor of 10.

(2) A procedure we developed for lead,bismuth, ruthenium, and technetium


Weapons Chemistry

incorporates the sample to be analyzedinto a small bead of borosilicate glass.This procedure, which virtuallyeliminates interferences from impuritiesin the filament material, is beinginvestigated for other elements.

(3) Negative ionization from a lanthanumoxide substrate provides even greaterionization efficiency for technetium.Although this process was not developedspecifically for weapons diagnostics, itshows great promise for solvingproblems in that area.

We also have under way a series ofinstrumental developments to increaseabundance sensitivity (the ability to measurea very small isotopic abundance adjacent to anisotope of very large abundance). Our standardsingle-stage instruments have an abundancesensitivity of approximately 1 x 105. We havebuilt two dual-magnetic sector instrumentsthat have demonstrated abundance sensitivitiesof 5 x 107. We now plan to add an electrostaticsector that should increase the abundancesensitivity to 2 x 109.

As a result of the developments in chemistry,ionization processes, blank control, andinstrumentation, we can achieve very lowdetection limits for the suite of elements shownhere.

Element Detection Limit

Uranium 5xl0 6 atomsPlutonium 5 x 105 atomsAmericium 2xl0 5 a tomsNeptunium 2 x 105 atomsBismuth 5 x 107 atomsTechnetium 2 x 106 atoms

Our ability to measure isotopes at these verylow levels has led to a number of importantspin-off studies, including the measurement ofactinide retention in human tissues; migrationof plutonium, technetium, and americium ineither uranium ore deposits or waste repositorysoil samples; studies of solar neutron flux;and examinations of the double-beta decayprocesses. In addition, our precise measure-ments of uranium and plutonium in very smallsamples has resulted in a program to safeguardthese materials in the nuclear processing cycle.

Isotope and Nuclear Chemistry Division Annual Report FY1988 17

Weapons Chemistry

Mass Spectrometers and IsotopeSeparators—Why Both?

Edwin P. Chamberlin

Two types of instruments at INC-Divisioncan be used to measure the relative abundancesof isotopes (isotopic ratio) within any givenelement: mass spectrometers and isotopeseparators. Although these two instruments aresimilar in many respects, they differ in others.

Both instruments use an ion source to removeelectrons (or add, in the case of negative ions)from atoms of the sample material. The ionsare then allowed to fall through an electricalpotential to reach the desired energy—10 kVfor spectrometers and 50 kV for separators.

In both instruments, the ions then enter atransverse magnetic field, where they aredeflected along a radius of curvature that isproportional to the square root of their mass.This magnet effects the separation of ionsof different mass. The magnet for a massspectrometer may weigh as little as 500 kg,whereas the magnet for an isotope separatormay weigh as much as 10 000 kg.

The ion current levels are also significantlydifferent: ~10'9 A in a mass spectrometer vs10"5 A in an isotope separator.

These instruments have optical properties likea camera or telescope. If properly designed, theywill provide an image of the ion source at a focalpoint downstream of the magnet. When ions ofvarious masses are emitted from the ion source,each mass will be brought to a focus at a differentposition downstream of the magnet. The locusof focal points is called the focal plane. It is atthis focal plane that mass spectrometers andisotope separators employ significantly differenttechniques to measure isotopic ratios.

The mass spectrometer usually has, at thefocal plane, a slit that is narrow enough topermit ions of only one mass to pass. A detectorbehind the slit determines how many ions persecond pass through. The field of the magnet isthen changed so that ions of a different masscan pass, and the detector determines how manyions per second of that mass are present. Theratio of the two detector count rates determines

the isotopic ratio of the sample loaded into thaion source, This ratio will be measured severaltimes to attain the desired confidence in themeasurement.

On the isotope separator, no slit is used andthe magnet is run at a constant field value.A long foil is placed at the focal plane and ionsof various masses are collected on it until thesample in the ion source is exhausted. Becauseeach isotope hits the foil at a specific location,isotopic separation is achieved. The collectionfoil is then cut midway between each of theisotopes. Each section of foil, which containsa single isotope, is loaded into a calibrateddetector to determine the number of radioactiveatoms present—and thus, the isotopic ratios ofthe sample.

Further details on mass spectrometer analysesmay be found in a companion article in thissection. The discussion below describes isotopeseparator operation.

Separation and CollectionWhen a nuclear device is to be tested, chemicaldetectors are loaded into the device so that wecan determine the neutron spectrum and flux atthe time of detonation. Neutrons from the deviceproduce a wide range of radioactive isotopesfrom the originally nonradioactive detector.Measuring the relative abundances of theseradioactive isotopes (isotopic ratios) is one of thepurposes of the weapons diagnostic program.We use the isotope separators to isolate specificisotopes from each other and from any fissionproducts that may be present in abundance.Separators must perform well in two areas if weare to make these measurements accurately.

After isotopic separation, the samples aresent to the counting room, where the numberof radioactive atoms on each foil segment isdetermined. A large number of radioactiveatoms makes this determination easier;therefore, the efficiency of ionization in the ionsource is important. Raising this efficiency from1 to 10% can reduce the counter time required,reduce the magnitude of background correction,and provide greater overall statistical accuracy.

There is no single solution to the problem ofionization efficiency. Each element behavesdifferently because of its vapor pressure andionization potential. The chemical compound

18 Isotope and Nuclear Chemistry Division Annual Report FY1988

Weapon* Chemistry

(and its purity) chosen by the chemist preparingthe sample can affect ionization efficiency. Forexample, rare-earth elements are ionized bysurface ionization techniques in which thesample atoms ^re vaporized and then contacta 3000 K tungsten surface. This method requiresloading the rare-earth sample as an oxide sothat it does not vaporize and escape before theionizing surface reaches the desired tempera-ture. But the preparation of oxides must bedone carefully to ensure that excessive alkalior alkaline earth compounds are not included.If such compounds are present, ionizationefficiency can be reduced by a factor of 10 to100 times.

In 1985, tailings were commonly at a ratio of10-3 to the main isotope. Today, tailings canusually be limited to the 10"* levei. Our goal isto consistently hold tailings to 10'5.

Not all samples are run for weaponsanalysis. The laboratory has many other usesfor separated isotopes; for example, if a pure"spike" isotope is loaded with a test sample,it can sometimes reduce the running timerequired on the mass spectrometers. Figure 1.2shows the periodic table from an ion sourceuser's point of view. For each element, thistable gives data that are useful in decidingwhich ion source will provide the best efficiency.

The second area of desired improvement isthat of separation purity. Not all ions of mass Mend up at the mass M position on the collectionfoil; some will be at the M+I position and somewill be at the M-l position—this phenomenonis called tailing. If the available quantity ofmass M atoms greatly exceeds that of mass M+latoms, a small amount of tailing might meanmore mass M atoms will be in the M+l positionthan mass M+l atoms themselves.

Any element that has a first ionizationpotential of 6.5 eV or less can be run with 10%or higher efficiency in the surface ionizationsource. Any element with a listed temperatureof 1100 K or less can be run in the plasma sourcewith 3% efficiency. Any gaseous element can berun in the microwave ion source.3

H5.4 K

13.6 eV-0.75 eV

Li670 K5.4 eV

-0 62 eV

Na465 K5.1 eV

•0.55 eV

Be1275 KS.3 eV

M

E l e m e n t

Temperature1st lonization Potentiale- Affinity

B1975 K8.3 CV

•0.2B eV

Al1250 K6.0 eV

-0.44 eV

c2400 K11.3 eV-1.26 eV

Si1615 K6.2 eV

•1.39 eV

400 K10.5 CV•0.75 eV

N32 K

14.5 eVo37 K

13.6 eV-1.46eV

330 K10.4 eV-2.08 eV

I-37 K

17.4eV-3.40 eV

C!110K13.0 K-3.62

HeIK

24.5 eVooetf

Ne10 K

21.6 eV

Ar36K

15.eeV

K395 K4.3 eV

-0.50 eV

Ca730 K6.1 eV-0.04

Sc1375 K6.6 eV

-0.19 eV

Ti1710K63 V6.3

•0.05VeV

1820KS.7eV

•0.S3 6V

Cr1430 K

Mn1020K7.4 eV

Fe1500K7.9 eV

•0.16';V

Co1530K7.9 eV

-0.66 eV

Ni1530K7.6 eV

•1.16 eV

Cu1300 K7.7 eV•1.23 eV

Zn520 K9.4 eV

Ga1175 K6.0 eV-0.3 eV

Ge

0VS.0•1.2 eV

As475 K9.8 sV0.80 eV

Se435 K9.8 ev

•2.02 eV

Br162 K

l i .BeV•3.37 eV

Kr49 K

14.0 eV

R b ' 3r

-0.49 e

Y1600 K6.2 eV

•0.31 eV

Zr2275 K6.8 eV

•0 43eV

Nb2550 K6.9 eV

•0.89 eV

Mo2400 K7.1 eV0.75 eV

Tc2350 K7.3 eV•0.6 eV

Ru2250 K7.4 eV• 1.1 eV

Rh1975 K7.5 eVI.UeV

Pd1450 K8.3 eV0.56 eV

Ap11CWK7.6 eV1.30 eV

Cd9.0 eV

In1000 K5.3 eV•0.3 ev

Sn1275 K7.3 eV•1.2eV

Sb700 K8.6 eV•1.1 eV

Te550 K9.0 eV

S 7 V

225 K10.5 eV•3.56 ev

Xef.3K

12.1 eV

Cs350 K3.9 eV0 47 eV

Ba730 K5.2 eV

La1700K5.3 eV•0.5 eV

Hf2275 T6.8 eV

Ta2850 K7.9 eV

-0.32 eV

w3000K8.0 eV0.82 eV

Re2e50K7.9 eV0.15 eV

Os2750 K8.7 eV•1.4 eV

IrS380K9.1 eV

•1.57eV

Pt2010 K9.0 eV

•2.13 eV

Au1400 K9.2 eV

•2.31 dV

Hg26?K10.4 ev

TI740 K6.1 eV•0.3 eV

Pb Bi790 K7.3 eV•0.95 eV

Po495 K8.4 eV•1 9eV

At

•2 9eV

Rn

Fr Ra690 K5.3 eV

Ac

Ce"1650 K5.5 eV

Th2250 K6.1 eV

Pr '1420 K5.5 eV

Pa

N d "1325 K5.5 eV

u1850 K6 2eV

Pm1050 K5.6 eV

Np

Sm"1

850 K5.6 eV

Pu1475 K6.1 eV

Eu730 K5.7 eV

Am1130 K6.0oV

Gd "I Tfa "1350 S 1425 K6.2 eV | 5.8 eV

1125K5.9 eV

H o "1225 K6.0 eV

Er1225 K6.1 eV

TrrT950 K6.2 eV

Yb '690 KS3 eV

Lu "1550K5.4 eV

Fig. 1.2. This chart shows the temperature required to reach 10'4-7brr pressure, the first ionizationpotential, and the electron affinity. A slash in the upper-right-hand corner indicates that we haverun that element within the past 3 yr and have some confidence in our ion source operatingparameters.

Isotope and Nuclear Chemistry Division Annual Report FY 1988 19

:-.. O

L / Biochemistry amd Nuclear Medicime

O v e r v i e w ,•-.-•• „••••—. = ; ; - w = - = ^ ^ \

If

Biosynthesis of the Coenzyme PyrroloquinolineQuinone

Lanthanide Schiff Base Complexes as ContrastAgents for Magnetic Resonance Imaging

BiomedicaT Applications for RadioisbtopeGenerators

Biochemistry and Nuclear Medicine

Biochemistry and Nuclear MedicineOverview

Pat Unkefer and Janet Mercer-Smith

Biomedical and nuclear medicine efforts inINC Division are centered in INC-4 and INC-11.The variety of projects under way in each areaare outlined here, and three specific projectsare discussed in detail in articles that follow.

BiochemistryThe Division's biochemistry activities includeresearch in several subcatagories of thisdiscipline: protein structure, metabolic studies,and synthesis and application of improvedmagnetic resonance imaging agents. Thesestudies are technically supported and comple-mented by the Division's expertise in producingand employing radionuclides as well as theseparation and use of stable isotopes.

Stable isotopes of carbon, nitrogen, and oxygenare routinely produced in large quantities in theDivision. These isotopes are powerful researchtools for answering fundamental questionsabout the way living systems function andspecific questions about the biosynthesis ofimportant components in biological systems.One class of essential biological components isthe cofactors used by enzymes to catalyzecertain steps in metabolism. These cofactors areoften the commonly recognized vitamins. Recentefforts use 13C combined with nuclear magneticresonance detection to study the route ofbiosynthesis for a newly recognized cofactor,pyrroloquinoline quinone. These studies readilyindemnified the biological precursors of thismaterial, providing yet another excellentexample of the accuracy and efficiency of thisexperimental approach. For the identification ofbiological precursors and their biosynthesis, thisexperimental approach is without equal. Newapplications of this method can be expected; forexample, recent studies have shown thatimportant regulatory actions are exerted bymetabolism upon gene expresssion in higherorganisms, but these systems are poorlyunderstood. The systems are clearly importantin such processes as development and growth innormal and abnormal cell types like cancer cells.Stable-isotope-assisted studies will be anexceptionally powerful tool as we examine themetabolically perturbed systems that will be

used to probe the complex relationships bywhich metabolites influence gene expressionof the very systems generating them. Anotherresearch effort seeks to understand theregulation of nitrogen assimilation by cells;this process is a working example of metabolisminfluencing gene expression and is carried out inmammals, higher plants, and microorganisms.

Other investigations include a character-ization of the detailed structure of the ironsulfur proteins that carry out the electrontransfer process of cellular respiration. Weare examining these proteins, whose geneexpression is controlled by the ferrous ironuptake system, as a complementary project inour characterization of the structure/biologicalrole of superoxide dismutase.

Studies of metabolism and protein structureare complemented by the function of theNational Stable Isotopes Resource. Thisresource is funded by the National Institutesof Health to help provide stable, isotopicallylabeled, biologically important compounds tothe basic research community. The resourceassists this community by developing efficient,steriospecific syntheses for specific-positionisotopic labeling of biological compounds notavailable from other sources. In this way, theResource supports the best and most significantbiological research—work at the cutting edge ofscience.

Nuclear MedicineWe conduct nuclear medicine research usingradioisotopes produced at the Los Alamos MesonPhysics Facility (LAMPF). During FY 1988,the Medical Radioisotopes Research Programshipped 30.1 Ci of radioisotopes (in 177shipments) to research institutions, industry,extramural collaborators, and intralaboratoryresearchers. Future radioisotope productionresearch and development will continue toemphasize beamstop processing for ^Ti, 26A1,and 32Si. These long-lived radioisotopes areproduced through the long irradiations thatare available at the LAMPF beamstop. One ofour current efforts is to expand the applicationsof electrochemistry in radioisotope separationsto obtain high-purity radioisotopes for medicaland biological research.

In other applications research, we have focusedon three areas: (1; development of biomedical



generators to make short-lived radioisotopesavailable to the nuclear medicine community,(2) development of methods to radiolabel smallmolecules and monoclonal antibodies, and(3) biological investigations of radiolabeledporphyrins as agents to image tumors.

Biomedical generators are used to separatelong-lived parent radioisotopes from theirshort-lived daughters. These separationmethods make available isotopes whose half-lives are too brief to make overnight shippingfeasible. Biomedical generators are alsodesigned to ensure a continuous, readily usablesupply of the daughter radioisotopes for clinicalpersonnel. Our current research is directed tothe development of three particular generators:(1) the lOgcd/^'nAg generator for ^™-Ag, anultrashort-lived isotope that is potentially usefulfor gamma-camera imaging with pediatricapplications, (2) the 8sZr/88Y generator for 8SY,a gamma-emitting isotope that can be used todevelop chemical and biological applicationsfor 90Y (Yttrium-90 is a beta emitter useful forinternal radiation therapy; however, investi-gating the biodistribution of beta-emittingcompounds is much more difficult than studyinggamma-emitting analogs); (3) the72Se/72Asgenerator for 72As, a radioisotope with potentialfor positron emission tomography imaging ofpathological processes and tumors.

Because 67Cu has nuclear decay propertiesthat are suitable for tumor imaging and internalradiation therapy, we are investigating "cold kit"methods to radiolabel antibodies with 67Cu.The specificity of the antibodies for tumorscarries the radioisotope to the tumor site forinternal radiation therapy or gamma-cameraimaging. Our cold kit method consists of anN-benzyl porphyrin covalently attached to anantibody; the porphyrin can be radiolabeledwith 67Cu under mild reaction conditions.This method of preparing the 67Cu-labeledantibody yields antibodies that have highimmunoreactivity and good localization inmouse tumors.

We are developing 67Cu labeled porphyrins todetect inflamed and neoplastic lymph nodes aswell as inflammatory lesions that cause feverof unknown origin. The ability to image diseasedlymph nodes gives us the ability to (1) detectnodal involvement in metastatic cancer and inlymphatic tumors, <2) stage cancer, (3) determine

cancer therapy modality, and (4) determine thephysical extent of infections. A diagnosticimaging agent for inflammatory lesions wouldalso locate abscesses. Our immediate goal isto determine the mechanism of porphyrinlocalization both in inflamed and neoplasticlymph nodes and in inflammatory lesions.The 67Cu porphyrin reaches a maximumconcentration in the inflamed lymph nodes;this concentration is 4 times greater than insurrounding muscle and 8 times greater thanin fat. Initial mechanism studies suggest thatmacrophages and T cells may be responsiblefor the enhanced uptake in inflamed lymphnodes. Preliminary studies indicate that the67Cu-labeled porphyrin is taken up by sterileabscesses and the surrounding inflamed tissuefar more than by normal tissue. An under-standing of this mechanism of porphyrinlocalization will help us determine theoptimum conditions for localization.

Another related area of nuclear medicineresearch is the development of 67Cu porphyrinsto image early, treatable stages of lung cancer.In a collaborative research project withphysicians at St. Mary's Hospital in Colorado,we are using porphyrins to analyze the sputumof uranium miners who have radon-inducedlung cancer. We have found that the porphyrinsgive us excellent recognition of tumor cellsin sputum. We hope to de^Telop radiolabeledporphyrins that can be used to image lungtumors at an early stage of cancer development,when the cancer is most susceptible totreatment.

Researchers in INC-4 and INC-11 arecollaborating on a project to design chelatingagents for paramagnetic metal ions, whichcan be used as paramagnetic contrast agentsfor magnetic resonance imaging (MRI),a noninvasive method of in vivo imaging.Because the paramagnetic metal ions are toxic,chelating agents that form extremely stablecomplexes with paramagnetic retaliationsare needed for paramagnetic contrast MRItechnology. We are currently developingchelating agents for gadolinium(III), theparamagnetic metal ion with the highestparamagnetic contrast effect for MRI. We'vehad some success with macrocydic chelatingagents that completely encircle the gadolinium.



Biosynthesis of the CoenzymePyrroloquinoline Quinone

Clifford J. Unkefer, David R. Houck, andJohn L. Hanners

We are attempting to understand the physiologyand biochemistry of methylotrophic bacteria;these soil-borne bacteria are unique because oftheir ability to grow by using simple one-carboncompounds such as methane or methanol astheir sole source of carbon and energy. Animportant component of this process is theoxidation of methanol to formaldehyde bymethanol dehydrogenase, which requires thecoenzyme pyrroloquinoline quinone (PQQ).This enzyme was first recognized as a cofactorfor the pyridine nucleotide-independentmethanol dehydrogenase from methylotrophs.4

These quinoproteins represent a novel class ofdehydrogenases that is distinct from the well-known pyridine nucleotide and flavoproteindehydrogenases.5 In these quino-dehydro-genases, PQQ serves as a 2e72H+ redox carrierthat donates electrons from the oxidation ofmethanol through an electron transport chainto O2 (Fig. 2.1).

Recent studies indicate that PQQ is alsoa cofactor for several well-known copper-containing amine-oxidases, including bovineserum amine oxidase, porcine kidney diamineoxidase, and human placental lysyl oxidase.6'7

This class of enzymes serves to cross-linkcollagen, which makes up the connective tissueof animals. The presence of PQQ in higherorganisms raises the question of how thisnovel compound is biosynthesized and whetheror not this compound or a related analogue is

oocr

COO' j ^ "

oPOQ

COO"

" , 2 H +

-QOC

COO" 1

O - H

PQQH2

COO'

(

?-O-H

a vitamin. None of the biosynthetic precursorsor intermediates had been identified untilrecently. Using specific 13C-labeling and NMRspectroscopy, we examined the biosynthesisof PQQ in the methylotrophic bacteriumMethylobacterium AMI.8-9 We demonstratedthat PQQ is biosynthesized from the twocommon amino acids L-glutamate andL-tyrosine (Fig. 2.2).

To determine the biosynthetic origin PQQ,we isolated PQQ from cultures of Methylo-bacterium AMI that were grown from either[1-13C] or [2-13C]ethanol as a carbon source.The labeling patterns in PQQ were comparedwith those obtained in amino acids purifiedfrom protein hydrolysates. The [1-13C] and [2-13C]ethanol labeling experiments, coupled withthe obvious structural homologies, provide aworking hypothesis for the biosynthetic originsof PQQ (Fig. 2.2). We believe that glutamateprovides N-6 and carbons 7', 7, 8,9, and 9'; theremaining portion is derived from a symmetricproduct (C2 axis through C-l' and C-4') of theshikimate pathway, likely tyrosine. The phenolside chain provides the six carbons of the ringthat contain the orthoquinone, whereas theamino acid backbone forms the pyrrole-2-carboxylic acid moiety.

To demonstrate directly that tyrosine is aprecursor of PQQ, we added [3'5'-13C2]tyrosineto Methylobacterium AMI cultures growing onmethanol.10 PQQ isolated from this culture wasexamined by ^H and 13C NMR spectroscopy.The 13C spectrum indicates that L-[3',5'-13C2]tyrosine labels PQQ at C-5 and C-9a aspredicted by the biosynthetic model (Fig. 2.2).

FIG. 2.1. PQQ acts as a 2em, 2H+ carrier in quino-dehydrogenases and cycles between the quinone(PQQ) and quinol (PQQH^ forms.

COO'Gluiamate I

' O O C ^ ^ N » H 'OOC

o o .

coo-coo- N—i

0

PQQCOO"

0

COO"^"N ^ \ Tyrosine

FIG. 2.2. Proposed biosyntketic precursors ofPtfQ.



Because C-9a is spin-spin coupled to H-8, !HNMR analysis can be used to determine the13C enrichment at C-9a. Under these cultureconditions, PQQ was labeled at C-9a (and C-5)to an enrichment of 63%. The resonances forC-5 and C-9a are doublets as a result of 13C-13Ccoupling, which proves that the phenol groupof tyrosine is incorporated intact into the ring ofPQQ containing the orthoquinone.

The results outlined above show that tyrosineprovides the six carbons of the orthoquinone-containing ring. To examine the possibility thatinternal cyclization of the tyrosyl backboneforms the pyrrole-2-carboxylic acid moiety, wecultured Methylobacterium AMI on a mixtureof [3',5'-13C2]tyrosine (50%) and [3-13C]tyrosine(5&%). The 13C NMR spectrum of PQQ isolatedfrom the culture filtrate contained only threeresonances corresponding to C-5, C-9a, and C-3.The 13C enrichments were determined by *£[NMR. The equal incorporation of 13C at C-3 andC-9a (41 and 42%, respectively) indicates thattyrosine is incorporated intact (Fig. 2.2).

As demonstrated from the results obtained inexperiments on Methylobacterium AMI, PQQarises from the condensation of glutamate andtyrosine. A possible route for the biosynthesisof PQQ is diagrammed in Fig. 2.3. In this route,tyrosine or some derivative of tyrosine isoxidized to dopachrome in a reaction catalyzedby a monophenol monooxygenase-like enzyme.Glutamate could form a Schiff base withdopaquinone. The cyclization of the tyrosinebackbone to form the pyrrole ring could occur bya Michael-type addition analogous to the knownnonenzymatic cyclization of dopaquinone to formdopachrome.11 Alternatively, dopachrome maybe an intermediate in the biosynthesis of PQQ.We are now identifying possible intermediates inthe biosynthetic pathway to PQQ. This researchproject contributes to our overall understandingof the physiology of methylotrophic bacteria. Thesamples of 13C-labeled PQQ generated duringthis research project are being used to examinethe chemical mechanism of methanoldehydrogenase. This enzyme plays the centralrole in the energy metabolism of methylotrophs.

COO'H3

+N —C,000"

COO'

PQQ

FIG. 2.3. Possible route of PQQ biosynthesis.

Isotope and Nuclear Chemistry Division Annual Report FY 1BS8 25


Lanthanide Schiff Base Complexes asContrast Agents for Magnetic ResonanceImaging

James R. Brainard, Paul H. Smith,David E. Morris, John H. Hall,Gordon D. Jarvinen, Robert R. Ryan,Dean A. Cole, Joanna Norman,Karen Bullington, Timothy Burns,Janet Mercer-Smith, Richard Griffey,*Mark Brown,* and Nick A. Matwiyoff*

Magnetic resonance imaging (MRI), a non-invasive method for obtaining images of objects,has many applications in medical diagnosis andresearch. MRI uses magnetic fields and radio-frequency radiation to localize the position ofatomic nuclei in space. Protons are the mostabundant and sensitive nuclei in biological tissues;therefore, most medical applications of MRIhave imaged protons. The protons in biologicaltissue are present primarily as water; conse-quently, MRI images primarily reflect the distri-bution and properties of water in the body.Because water is centrally involved in manybiological processes, and because the methoddoes not use ionizing radiation, MRI is rapidlybecoming a preferred imaging method fordiagnosis of many diseases, including multiplesclerosis, stroke, and cancer. This project focuseson designing, synthesizing, and evaluatingparamagnetic complexes that can be used toimprove the differences (contrast) in MRI images.

The properties reflected most directly in MRIimages are the amount of water contained in thetissue (proton density) and the rates at whichthe water protons return to their ground stateenergy levels (relaxation rates). Although manytissues and disease states naturally exhibitdifferences in proton density and relaxation rates,MRI contrast agents could be developed to enhancethe differences in MRI intensity between varioustissues and between healthy and diseased tissue.One way to increase relaxation rates of wateris by adding paramagnetic metal ions. If para-magnetic metals are differentially taken up bytissues, relaxation rates of water in those tissuesare increased, and they appear light in MRI images.

One problem with using paramagnetic metalions in living organisms is that the metals are fre-quently toxic. To reduce toxicity, researchers usecomplexes of paramagnetic metals with organicligands, thereby lowering the concentration of

the toxic free metal ion.1- Present NMR contrastagents such as GdDPTA rely on the thermo-dynamic stability of multidentate complexes toreduce the toxicity of the free metal. Unfortunately,the first coordination sphere of the paramagneticmetal is primarily occupied by coordinatinggroups from the ligand and efficient relaxationof water protons is limited. Our approach todesigning stable paramagnetic complexes withmultiple water coordination sites *s to usemacrocyclic ligands with high kinetic stability.

The lanthanide Schiff base maerocycles synthe-sized by Vallerino and coworkers13 (illustratedbelow) appeared to be good candidates for MRIcontrast agents. We refer to these complexes asLnHAM, for lanthanide HexaAzaMacrocycles.A particular advantage of these systems is thatthe synthesis can be accomplished in one stepby using a template approach. The ease andversatility of synthesis make Schiff base macro-cycles an especially attractive system in whichto examine structure-activity relationships.

= LnHAMLn = La Ihrobgn Lu

> < J

'Center for Non-Invasive Diagnosis, University ofNew Mexico, Albuquerque, New Mexico.

The first step in evaluating the potential ofthese complexes as MRI contrast agents was tomeasure their effectiveness as relaxation agents.Relaxivity is defined as the change in solventrelaxation rate per concentration unit of therelaxation agent. The relaxivity of GdHAM inaqueous solution was 9.7 s*1 mM 1 at 0.47T;by comparison, the relaxivities of gadoliniumaquo ion and GdDTPA are 9.1 aud 4.1 s^mM"1,respectively. The relaxivity of the GdHAMcomplex is significantly greater than that forGdDTPA and slightly greater than that for thegadolinium aquo ion, which suggests that theexpectation of increased relaxivity in complexeswith multiple open coordination sites is realized.To more completely understand the effects of theligand structure on the relaxivity of paramag-netic complexes, we investigated the solid stateand solution properties of the europium andgadolinium complexes by x-ray diffraction,electron and nuclear magnetic resonance,cyclic voltametry, and luminescence lifetimemeasurements.14 A ball and stick representationof the single-crystal x-ray structure of the[GdHAM(Acetate)2]+ is shown in Fig. 2.4.The gadolinium atom sits in the cavity of themacrocycle, and two acetate anions occupy the


Biochemistry and Nuclear Meditina

coordination sites above and below the macro-cycle, making the complex 10-coordinate. Thisobservation and luminescence lifetime measure-ments suggest that the complex has 3 to 4coordinated waters in solution.

A very important requirement for a successfulclinical MRI contrast agent is low toxicity. Usinga sensitive cell growth inhibition method, weperformed a preliminary toxicity study onGdHAM compared to GdDTPA. Figure 2.5shows that both GdHAM and GdDTPA inhibitgrowth compared to the control; however, thetoxic effect of GdHAM was considerably less.

The specificity of GdHAM for tumors was demon-strated by MRI of a canine glioma tumor modelin a rat. Tumors were implanted into the flanksof two rats 7 days before MRI. One rat was imagedusing GdHAM as a contrast agent and the otherusing GdDTPA at the Center for Non-InvasiveDiagnosis (Fig. 2.6). The tumors appear as areasof white intensity in the right flank of each rat.These images, taken at various times after injec-tion of the contrast agent, show that GdHAMand GdDPTA give similar contrast to the tumor5 min after injection. However, in the second,third, and fourth images, the tumor image in theGdHAM-treated rat is significantly brighter. Theslower washout exhibited by GdHAM is a poten-tial advantage for clinical imaging because it is

FIG. 2.4. This side view of the GdHAMiAcetate)2complex shows the acetates coordinated aboveand below the gadolinium metal as well as thebending of the macrocycle in the solid state atthe diamine hinges. (Yellow = gadolinium, blue= nitrogen, white = hydrogen, black = carbon,and red = oxygen.)

o

ime

nitn

Cel

d

Is/

CD

o

No.

FidOU

50

40

30

20

10

r\U

* » • 60DTPA" • • GdHAM••» Contr!

>

/

) 24 48

Time (h)

//

//f

y

- »72

FIG. 2.5. Growth inhibition toxicity assay of GdHAMand GdDTPA.

difficult to obtain high-contrast MR images onmany low-field MRI instruments in only 5 min.

The GdHAM complex shows significantpromise as an MRI contrast agent because of itshigh relaxivity and kinetic stability. In addition,our preliminary in vitro toxicity data and invivo MR images of a tumor model in rats suggestthat it may be more efficacious than GdDTPA.Although we need to more completely define thestructural and dynamic properties responsiblefor the high relaxivity and stability of thiscomplex, the concept of designing macrocyclicligands for gadolinium (III) clearly showspotential for improved MRI contrast agents.By performing structure-activity studies inthese systems to identify the key factors thatdetermine relaxivity, stability, tissue specificity,and toxicity, we hope to develop a rational basisfor contrast agent design.

FIG. 2.6. In them: MRI experiments with tumor* m tworats, the rat on the right was given GdHAM and therat on the left was given GdDTPA. The images K*n>obtained (from upper left) 5,20,35, and 50 min afterinjection.

Isotope and Nuclear Chemistry Division Annual Itvport FY 1388


Biomedical Applications forRadioisotope Generators

Dennis R. Phillips, Frederick J.Steinkruger, and Wayne A. Taylor

Nuclear medicine owes its existence to theAnger camera and the development of the99Mo/99mTc biomedical generator system.A generator is a system in which a short-liveddaughter isotope is quantitatively separatedfrom its longer lived parent. Depending upon thegenerator and application, the daughter mightbe used directly for diagnosis or therapy orconverted to an appropriate chemical formfor medical procedures. For daughters withultrashort half-lives, this is the only wa3r toefficiently and economically provide the isotopeto the nuclear medicine community. With theappropriate parent/daughter combinations, itis possible to provide isotopes for positronemission tomography, single-photon-emissioncomputed tomography imaging, and therapy.

It was the 99Mo/99mTc generator thatpermitted routine clinical applications of nuclearmedicine imaging techniques, and it is still themainstay of nuclear medicine. However, thisgenerator has a number of shortcomings,including a brief parent half-life and lack ofdaughter emissions suitable for therapeuticapplications. Therefore, the development ofother generators with appropriate parent/daughter combinations may be very beneficialto nuclear medicine in the future.

Since its inception, the Medical RadioisotopesResearch Program in Group INC-11 has workedto develop new biomedical generators. The68Ge/68Ga and 82Sr/82Rb generators investigatedhere are now being used in the nuclear medicinecommunity. We are presently investigatingiO9Cd/iO9mAg, 72ge/72AS) ^ d 88Zr/88y generators.

The lOSCd/^nAg GeneratorIn this generator, the daughter 109mAg,which decays with a 39.6-s half-life to stable109Ag, is suitable for first-pass angiography withmultiple repeat studies. The short half-lifepermits higher doses that result in sharperimages but also reduces the radiation exposureto the patient. Because of the parents long half-life, we must use inorganic ion exchangematerial to avoid possible radiolysLs of organic-based exchangers. The daughter's ultrashort

half-life requires physiologically compatibleeluents to permit direct injection into patients.Dosimetry calculations indicate that we mustminimize 109Cd in the eluate—"breakthrough"—to reduce the patient's radiation exposure.Breakthrough is reported as the ratio of 109Cdin the eluate to that loaded on the generator.

Using a sodium-thiosulfate eluent, wesurveyed commercially available inorganicexchanger materials and discarded manybecause of mechanical problems in making acolumn. We investigated Photi D, a form oftitanium phosphate, because initial resultsshowed a high silver yield with a moderatecadmium breakthrough. After extensiveexperimentation, we also discarded Photi-Dbecause we were not able to reduce cadmiumbreakthrough to an acceptable level. We finallyreturned to Phostain, a form of tin phosphatethat had exhibited reasonable silver yield withlow cadmium breakthrough (Fig. 2.7).

We investigated the possibility of operatingthe column at elevated temperatures to enhancethe lO9mAg yield. Raising the column temperatureincreased the daughter yield to a maximum of71%; however, if the temperature exceeded 36'C,there was an unacceptable increase in cadmiumbreakthrough (Fig. 2.8). When we installed asmall filter containing ~50 mg of cationexchange resin on the outlet of the column,there was no statistically significant change inthe silver yield, but there was a substantial dropin cadmium breakthrough (Fig. 2.8). It was notclear whether this drop was the result of ionexchange or filtration of submicron shards ofPhostain. When we used scanning electronmicroscopy to examine the surface of the

g>m

Silver Recovery i%)

FIG. 2.7. Silver yield and cadmium breakthroughprofiles from a cadmium/silver generator.

28 Isotope and Xuclenr Chemistry Division Annual Report FY 1U88


o

4 I3 S

2 1

26 32 36

Temperature (°C)•Results with a cation stripper on generator

FIG. 2.8. Yield and breakthrough vs operatingtemperature.

inorganic ion exchanger particles, we observedsubmicron shards on the surface of the sievedparticles (Fig. 2.9). We can remove these shardsby wet sieving techniques. This may help thebreakthrough problem.

An Electrochemical 72Se/72As GeneratorRadioarsenic could prove to be a versatileand powerful agent in nuclear medicine. Wecould use some arsenic-containing compounds toimage and study metabolic activity in most organsystems—the brain and skeletal systems aretwo proven examples. Monoclonal antibodieslabeled with radioactive arsenic could be employedfor imaging and possibly therapy in cancerstudies. Arsenic-72 is a particularly promisingisotope: a positron emitter, it is potentiallyvaluable in positron emission tomography. Its26-h half-life is long enough to allow synthesisof radiopharmaceuticals, but short enough tominimize radiation doses in patients. Thedevelopment of applications will depend upon areliable supply of the isotope. Probably the bestapproach for 72As production is through a72Se/72As radiochemical generator system.

We have developed a dependable method forproducing 72Se in a rubidium/bromide targetirradiated at the LAMPF 800-MeV linear accel-erator.15 We dissolve the target in water, acidifythe solution, add copper(II) ion and seleniousacid carrier, and electrochemically depositselenium isotopes as Cu2Se at a platinum gauzeworking electrode. This deposition leavesarsenic in solution, which suggests that electro-chemical separation can serve as the basis of aradiochemical generator. We are developing aprocess to strip the selenium into an appropriateelectrolyte, allowing the 72As to grow in by nuclear

decay. Using this process we have obtained a99% radiochemically pure 72As traction.

The 88Zr/88Y GeneratorYttrium-90 shows promise as a tool for internalradiation therapy because of its beta emission;however, research in labeling monoclonal anti-bodies with 90Y has been hampered by the lackof suitable gamma emission by which the isotopecan be traced. Yttrium-88, with its long half-life(106 days) and several gamma rays, is a goodsubstitute for developmental applications. Forlabeling applications, we need an isotope that isavailable in very high specific activity (the ratioof radioactivity to mass of the element). Wedeveloped a procedure to recover 88Y from thedecay of 88Zr with a specific activity near thetheroetical maximum (lx 104 Ci/g). The 88Zr wasproduced by irradiating a molybdenum target atLAMPF. The molybdenum was dissolved withhydrogen peroxide and the resulting solutionwas passed through a cation exchange resincolumn. The zirconium was retained, and wewashed the molybdate through the column withhydrogen peroxide. We stripped the zirconiumfrom this column in SM HC1 and purified it byloading it onto an anion column and washingwith 12M HC1. The zirconium sticks, and thecontaminants are eluted. We removed a purefraction of 88Zr from the anion column in 2M HC1.

Yttrium-88 was allowed to grow in as the 88Zrdecayed and was separated by a repetition of theanion column procedure. This method produced88Y that has no observable radioactive contam-inants and minimal stable isotope contamination;it is suitable for development of labelingprocedures and for biodistribution studies.

FIG. 2.9. Scanning electron micrographs of Phoxtain(top) and Photi-D (bottom).

hotope and Nuclear Chemistry Division Annual Report FY

GeochemUtry and Environmental Chemistry

Overview

Thermodynamic Properties of Aqueous Solutions atHigh Temperatures and Pressures

Geochemical Measurements Suggest WidespreadCirculation of Ocean Ridge Material

Trace-Element Variations in the Fumes of Kilaueaand Mauna Loa Volcanoes

Geochemistry and Environmental Chemistry

Geochemistry and EnvironmentalChemistry Overview

Robert W. Charles

INC Division's increased involvement ingeochemical and environmental programsreflects the Laboratory's growing commitmentto these research efforts. National concern aboutdiminishing resources, basic energy shortages,and atmospheric and aquifer pollution, as wellas an increasing demand for waste disposal haschallenged us to find successful, efficient, andcost-effective methods to solve these problems.

Basic Energy SciencesInvestigation of rock-water interactions andelement migration includes experimental andcomputational modeling of rock-fluid reactionsin hydrothermal systems. These models areapplicable to environments that are appropriatefor the discovery and recovery of energy—whethergeothermal or fossil. For the Continental ScientificDrilling Program, we collect samples and investi-gate experimental/computational hydrothermalreactions of various natural hydrothermalsystems such as Sulphur Springs, VC-2a andVC-2b in the Jemez Mountains, and the deepSalton Sea well in California. Using a recentlydeveloped nuclear microprobe, we analyze major-,minor-, and trace elements in rocks and fluids todetermine the state of equilibrium in these geo-thermal systems. We use experimental hydro-thermal systems that consist of flexible reactioncells (gold and titanium) to study reactionrelations of phase assemblages in concentratedbrines. Solubility measurements are thenemployed to improve mathematical models ofthe natural systems.

We use flow calorimetry to measure thermo-dynamic properties of aqueous solutions at hightemperatures and pressures. These measurementsare ideal because the data can be integrated asa function of temperature to determine solutionenthalpies and total free energies. We have heatcapacity data for a number of aqueous chlorideand sulfate bearing systems. Our goal is toprovide data to 400°C so that we can study thebehavior of electrolyte solutions in the regionvery near the critical point of water. Integratedheat capacities also can be used in modeling.

Laser Raman investigations of mineral/organicinteractions in aqueous systems focus on aqueousspeciation, which is important in a number of

geochemical environments. We developed a high-temperature Raman cell to stud3r aqueous brinesup to 400°C and 1 kbar. We've examined zincbromide and chloride in our initial .studies ofelemental transport in geothermal systems.By investigating silica-organic acid complexing,we can determine the extent of silica transport,in, for example, hydrocarbon reservoirs, whereorganic complexation is dominant. Metalspeciation in organic systems such as thetransport of elements in acetate- and polymaleic-acid-bearing systems will help us model fulvicand humic acid movement in natural waters.

The technetium geochemistry programdeveloped "Tc as a natural tracer for someaqueous environments. Technetium, formed bynatural fission of uranium, decays with a half-life of 2.13 x 105 yr and comes to nuclearequilibrium with the parent in ~1 x 106 yrif there is no geochemical fractionation in thenatural environment. Technetium geochemistryhas practical relevance in our plans to store high-level nuclear waste underground and as a chrono-meter for physical and chemical processes in thesub-surface. The ultratrace-element abundanceof technetium required that we develop chemicaland mass spectrometric techniques to detectconcentrations of l(r12 g/g uranium.

We use solid source mass spectrometrymeasurements of 238U-230Th disequilibrium ingeologic systems to examine the geochemistry ofsuch systems on the million-year time scale. Massspectrometer techniques greatly reduce samplesize and increase precision. When the techniquewas applied to "zero aged" dredged basaltsamples from the Juan de Fuca Ridge axis, initialresults showed fractionation effects caused bymagmatic processes; this same method will beapplied to the young (<350 000-yr) flows sampledin VC-1, in the Jemez Mountains.

Two articles in this section describe othertrace-element studies: one of volcanic gases andparticles and the other of samples from asteroid-impact-induced extinction boundaries around theworld.

When many of our field investigations requireda technologically advanced fluid and gas sampler,we developed a slick-line-based tool to collectuncontaminated fluid in the difficult environ-ments encountered in the Continental ScientificDrilling Project. We tested a gas-tight,l-/ capacityprototype sampler made of titanium Beta-Csuitable for brine salinities above 300°C.



Atmospheric SciencesWe are a part of the Winter Haze IntensiveTracer Experiment, a consortium of publicutilities and governmental agencies examiningthe origins of visible haze in the southwestern US.Los Alamos provides expertise in complex-terrainmeteorology (ESS Division) and atmospherictracer technology (INC Division) for conductingan atmospheric tracer experiment. Heavymethane (CD4) was released from the stack ofthe Navajo Generating Station for 6 weeks inwinter 19S7. Preliminary indications are thatthe tracer-tagged emissions from the power plantwere generally confined to the immediate vicinity,but haze events were detected from CanyonlandsNational Park to Grand Canyon National Park.We infer that there are other, unidentifiedsources that contribute to winter haze in thesouthwestern US.

The DNA dust characterization project attemptsto (1) determine the quantities of dust lofted bypre-1962 atmospheric nuclear tests and contem-porary high-explosive events and (2) characterizeits particle-size distribution and mineralogy.We obtain details of the dust's source by placingelemental and organic tracers in the test bed andsampling with both airplane- and truck-mountedsamplers; the data are used to assess operationaland environmental impacts of such explosions.

Nevada Nuclear Waste IsolationIn one of this program's many related tasks,we measure the distributions of cosmogenic andfallout radionuclides at Yucca Mountain, Nevada,to characterize the infiltration of precipitationand the velocity of water movement throughthe unsaturated zone at this potential high-levelnuclear waste repository. The US GeologicalSurvey provided cuttings to a depth of 1270 ftinto the unsaturated zone. Multikilogram samplesof the cuttings are ground and leached to obtainchloride samplers for 36C1 analyses performed atthe University of Rochester's tandem acceleratormass spectrometer. We will use 36Cl's 3 x 105 yrhalf-life to time the water-borne transport ofchloride through the unsaturated zone.

We are measuring effective diffusivity coeffi-cients under in situ conditions in two tuffs thatwill be penetrated by the exploratory shaft atthe potential Yucca Mountain repository. Datafrom this test will be compared with data fromlaboratoiy measurements and computer modelsto help vp'^date nuclear waste transportcalculations. A prototype diffusion, test beingperformed at the Nevada Test Site's G-Tunnel

will develop and demonstrate drilling, instru-mentation, and analytical techniques to be usedin the exploratory shaft diffusion test.

We also are using hydrothermal geochemistryto create a model of past and future mineralalteration in Yucca Mountain. The model willexplain (1) natural mineral evolution resultingin stable phase assemblages and (2) the effectsof a repository placed there. A model of mineralalteration in Yucca Mountain suggests thatmineral transformations observed there areprimarily controlled by aqueous silica activity.The rate of these reactions is related to theevolution rate of metastable silica polymorphs,assuming that SiC^aq) is controlled at theequilibrium solubility of the most soluble silicapolymorph present. Rate equations accuratelypredict the present depths at which thesepolymorphs disappear; rate equations are alsoused to predict future mineral alteration in thepresence of a high-level nuclear waste repository.

We are determining the concentrations andspeciation of important nuclear waste elementsthat could be released to Yucca Mountain'sfar-field environment if the repository werebreached; the critical elements are neptunium,plutonium, and americium. We study reactionsof ligands that are strong complexers of actinideelements, which are common in the groundwaterat the proposed site. This work is made moredifficult because the pH regime of typicalgroundwaters (near 7) implies that mostactinide elements have solubilities of >10"7lf.To measure these low levels,we are developing?. state-of-the-art photo-acoustic spectrometerfacility.

We must be able to predict radionuclidemovement from a potential repository to theenvironment. Using crushed-tuif, intact-tuff,and fractured-tuff columns, we investigate theeffect of kinetics, dispersion, diffusion, speciation,and nitration on the transport of radionuclides.We also are studying the variability of poretortuosity and constrictivity to determine therate of movement of radionuclides through tuffin the absence of an advective flux, the diffusivityof radionuclides as a function of saturation inblocks of intact tuff, and the time-dependenceof radionuclide uptake in solid tuff.

Isotope and Nuclear Chemistry Division Annual Report h'Y 1888 33

leochcinistrv and Environmental Chemistry

Thermodynamic Properties of AqueousSolutions at High Temperaturesand Pressures

Pamela S. Z. Rogers

It is important that we understandthermodynamic properties of electrolytesolutions at high temperatures when we arestudying geothermal systems, hydrothermalalteration processes, and elemental transportin deep brines such as those encountered inthe Continental Scientific Drilling Program.To model cementation, mineral digenesis,and element transport in sedimentary basinevolution, we need to know the propertiesof carbonates, hydroxy species, and organiccomplexes to at least 473 K. Our investigationwill determine the total free energies ofgeochemically important ionic species inaqueous solutions over a wide range ofcomposition and temperature. Because thenumber of different electrolyte solutions ofinterest at high temperatures is large, wewant to find a method of obtaining thermo-dynamic properties from a minimum amountof experimental data. Heat-capacity measure-ments are ideal for this purpose because wecan integrate the data to yield enthalpy andfree-energy information by using literaturedata available (for room temperature) toevaluate the integration constants. High-temperature free energies determined in thismanner can be used directly in calculations ofmineral/solution equilibria.

We have constructed an automated, flewcalorimeter to measure the heat capacities ofsingle and mixed electrolyte solutions over atemperature range of 298 to 673 K and atpressures from saturation to 50 MPa. The heatcapacity is determined by measuring the powerrequired to raise the temperature of a fluidby a precisely measured amount. The experi-mental fluid is pumped through 4-mm,corrosion resistant, capillary tubing; thenecessary heaters and temperature sensorsare placed on the outside of the tubing.Long lengths of tubing are wrapped aroundtemperature controlled blocks to ensure thatthe fluid inside reaches a constant, knowntemperature before the heat capacity isto introduce samples, and even change thepressure of the fluid inside the tubing, without

disturbing the thermal stability (and hence, thecalibration) of the calorimeter.

Generally, the calibration of flow calorimetershas been complicated by experimentaldifficulties; researchers report that two differentmethods of calibration give different results.However, we have shown that the two methodsgive the same results if corrections are madefor differences in experimental conditions.In addition, we have obtained calibration resultsthat are an order of magnitude more precisethan those previously available. This isimportant, because previous calibrationmethods introduced an absolute error up to25 times as large as the precision of a heatcapacity measurement for high-temperature,concentrated solutions Our results reducethe error introduced from calibration until it isabout equal to the precision of a heat capacitymeasurement. This improvement stemsprimarily from the complete automation ofour flow calorimeter, which allows us to measuremore precise, time averaged values of manyexperimental parameters. Results from heatcapacity measurements of the system Na2SO4-NaCl-H2O are shown in Fig. 3.1, where the

acity

(J-

8c5

Xu

Cil

CDQ .CO

5.0

4.5

4.0

3.5

0

w \ ^JV \I l" L \*. \ Tv. \

\»\ \ \

•4m NaCI

0.5

MolaliiyNa2

^ © 548 K

-

©4 0.5m NaCI ~

s ^ " > -2m NaCI^*S J

1.0

S04

FIG. 3.1. Specific heat capacities of mixtures in thesystem. Na2SO4-Na.Cl-H.jO have been superimposedby plotting the difference of the heat capacity ofthe mixture and that of the appropriate amount ofadded NaCl(aq). The properties of the mixturesare not predicted by simple addition of the twrectproportions of the two end members' properties.



specific heat capacities of NaoSO4(aq) withvarious amounts of added NaCl(aq) have beenoverlaid by subtracting the appropriatecontribution of NaCl(aq) to the mixture.The divergence of the heat capacities of themixtures from the curves for pure Na2SO4shows that the properties of the mixtures arenot simply additive. Instead, the C1-SO4

interaction also must be taken into accountwhen modeling the mixtures.

Heat capacity data can be integrated directlyto provide total free energies that can be usedto calculate mineral/solution equilibria.However, many commonly used computermodeling codes require activities, rather thantotal free energies, as input parameters.The two quantities are closely related; theactivity is a function of the difference betweenthe free energy of the real solution and that ofan ideal solution under the same conditions.The calculation of activities is usually done byextrapolating the heat capacity data to infinitedilution and then calculating the excessproperties as the difference between the totalheat capacities and the infinite dilution value.The excess heat capacities can then beintegrated to obtain activity values.

Unfortunately, at temperatures above 523 K,the extrapolation to infinite dilution requiredto calculate activities from the total freeenergies can not be done from the heat capacitydata alone. Additional thermodynamic data areneeded, such as heat of solution measurements(which are extremely difficult to obtain at hightemperatures) or ion-paring constants fromconductance or spectroscopic studies. In turn,the interpretation of these results is oftenambiguous and information on manyelectrolytes is not available. Figure 3.2illustrates the difficulties encountered in theextrapolation to infinite dilution for Na2SO4.The "best guess" value for the infinite dilutionheat capacity derived from one heat of solutionmeasurement is very different than otherextrapolated values, especially that chosenin a widely used solution modeling program.The difference in the latter two values, whenintegrated, would lead to an order of magnitudedifference in an equilibrium constant for areaction involving Na2SO4.

Alternatively, the use of the total free energiesrequires a recalculation of the equilibrium

constants needed in the morld so that theyreflect the new free-energy values yet remaininternally consistent. Such a recalculation isprohibitive for any but the smallest modelingprojects.

We are in the uncomfortable position ofhaving excellent quality data available to veryhigh temperatures, yet no really good way touse it. Our future work in this area willnecessarily involve developing appropriateestimation methods for determining the muchneeded infinite dilution properties.

CD

Na2SO^573 K. 20 MPa-

L •j*"Pi!2er" Extrapolation

2 x NaCI Value

"Best guess" from heatof Solution datum

•3.47 Value from Helgeson's "SCPCRTData Base

0.? 0.4 0.6 O.B 1.0

(molalily)12

FIG. 3.2. In this comparison of various methodsof extrapolating to infinite dilution, the Pitzerextrapolation accounts for possible ion-pairformation only in an indirect manner. Theextrapolation based on NaCI properties isbased solely on electrostatic arguments.

Isotope and Nuclear Chemistry Division Annual livport F}' 7.W.S' ,V.5


Geochemical Measurements Across theLate Cenomanian Extinction Interval:Evidence Suggests WidespreadCirculation of Ocean-Ridge Material

Charles J. Orth, Moses Attrep, Jr., andLeonard R. Quintana

A globally recognized extinction of certainplankton and molluscS;OCcurred in the LateCretaceous ocean just before and at the 92-MyrCenomanian-Turonian (C-T) stage boundary.The C-T event occurred about 26 Myr beforethe classic Cretaceous-Tertiary extinctionboundary, where there is evidence of a massiveearth/meteor impact. Results of geochemicalmeasurements across the C-T zone shouldprovide a strong test of recent hypotheses16"18

that suggest impacts, on Earth from cyclic cometswarms in the inner Solar System were thecause of periodic extinctions (26 Myr) of life.19

During much of the Cretaceous Period, ashallow sea covered the western interior ofNorth America from what is now the Arcticshore of Alaska to the Gulf of Mexico.Maximum eustatic flooding of our planetduring the Cretaceous began just before theC-T boundary and peaked in the EarlyTuronian. Erosion and tectonic uplift of thesemarine rock sequences have left many excellentexposures on outcrops and in roadcuts inwestern North America.

Last year we reported the results of ourstudy of the classic C-T exposure just west ofPueblo, Colorado, and gave some preliminarydata for other localities in Kansas, Nebraska,and Manitoba. In particular, we discovered twoiridium abundance peaks that coincided withforaminiferal and molluscan extinctions in theLatest Cenomanian marine rocks.20 Theconcentration of iridium is 1000 to 10 000 timeslarger in meteorites than it is in average Earthcrustal rocks, so an iridium concentration spike(anomaly; in sedimentary strata has been usedto indicate fallout from a large-body impact.Although large-body impacts with Earth couldhave provided the excess iridium we observed,such a scenario does not account for the excessscandium, titanium, vanadium, and manganesethat accompany the iridium anomalies. Wesuggested that a more plausible source of theexcess iridium and other elements (especially

chromium) was some form of deep-source 'uppermantle) volcanism; however, numerouseruptions at that time by continental <silicic)volcanoes were not the cause.

To further localize the source of theseelemental abundance anomalies, this year weconcentrated our measurements on sectionsalong the western margin of the ancient seawayin Arizona and Utah, farther to the south andcloser to the proto-Caribbean Sea in west Texas,and in western Europe (England and France).Abundances for about 40 elements in oursamples were provided by the Los AlamosResearch Reactor Group (INC-5) using theirautomated neutron activation analysis system.We also irradiated duplicate samples in intenseneutron fiuences and we radiochemicallyisolated iridium, platinum, and gold from .

Carbonate - Tree basis

FIG. 3.3. Abundances find ratios are shown forsome selected elements across the Cenomanian-Turonian extinction horizon that is exposed onoutcrop at Chispa Summit, south of Van Horn,Texas. The extinction of the foraminifer genusRotalipora precisely coincides with the loweriridium peak. Some molluscs and otherforaminifers disappear at the upper iridiumpeak.



FIG. 3.4. This map indicates relative deposition ofiridium. in the Late Cenomanian extinction intervalacross the western interior of North America. Theapproximate shoreline of the Late Cretaceous (~92 Myr)Epeiric Seaway is shown.

interfering radioactive nuclides. The resultsof measurements on a section near Van Horn,West Texas (Chispa Summit section) are shownin Fig. 3.3. Although we measured abundancesover a stratigraphic span of 47 m (equivalentto ~3 Myr of deposition), only the crucial extinc-tion interval is shown here because abundancesof the significant elements are very low andconstant in the rest of the section. However,strong hafnium and thorium peaks, which areassociated with ash beds from continentalvolcanic eruptions, occur throughout the entire47-m interval. To determine the distribution ofiridium in the western interior, we integratedthe amounts above background level at each ofour 16 measured localities (the pattern is shownin Fig. 3.4). Similar results were obtained forthe other enriched elements.

The pattern shown in Fig. 3.4 suggests thatthe excess of iridium (and other elements) mighthave come from the proto-Caribbean/Atlanticregion, so we obtained samples from a deep-water carbonate section in southern England.The results of these measurements from BeachyHead are shown in Fig. 3.5. Once again, twopeaks are observed, but at about 10% theintensity found at the strongest North Americanlocalities. Recent measurements on a platformcarbonate section in southern France failed tolocate the anomalies. Perhaps the sedimentswere eroded by wave action.

We cannot completely preclude large-bodyimpact sources for the elemental abundanceanomalies; however, the abundance patternsand ratios are better compared with those fromocean ridge basalts and mid-ocean tholeiiticlavas. We suspect the anomalies are the resultof increased spreading center activity in theLate Cenomanian North Atlantic/Caribbeanregions and/or the deep-water opening of theAtlantic (separation of South America fromAfrica) and the beginning of the North Atlanticgyre (clockwise circulation of the ocean currents).The circulation scenario fits the extinctionproblem because it would result in upwellingof deep anoxic water onto the outer shelf andcontinental margin communities that thrived onoxygenated water conditions. The depositionalpatterns we observed further suggest that theenhanced elements were deposited in the form ofmicroscopic particles carried by ocean currents,rather than by absorption from solution (as ions)on and in clay particles in the local sediments.Thus our evidence from the C-T extinctioninterval does not support the cyclic comet swarmhypotheses discussed above.

Much more work must be done before firmconclusions and models can be drawn. Plannedwork on Deep Sea Drilling Project cores from theAtlantic and Pacific Oceans and further work onEuropean localities should provide the necessaryclues.

FIG. 3.5. Abundances and ratios for someselected elements are shown for the LateCenomanian extinction interval exposed atBeachy Head (near Eastbourne), on thesoutheast coast of England.

Isotope and Nuclear Chemistry Division Ann ual Report FY 1988 37


Trace-Element Variations in the Fumesof Kilauea and Mauna Loa Volcanos

David L. Finnegan, Bruce M. Crowe, andTheresa L. Miller

Volcanos have long captured the imaginationof man. Whether the powerful, pyroclasticexplosion of a Mt. St. Helens or the fire-fountainof lava from a Kilauea, volcanic eruptions arefearful and wondrous events. In addition totheir obvious dramatic and aesthetic fascination,these massive events pi'ovide opportunities tostudy chemical and physical processes occurringbeneath the earth's surface. To further thisresearch, we collected fumes from volcanosbefore, during, and after eruptions to determinethe trace metals and acidic gas chemistry ofvolcanic fumes and their relationships tovolcanic eruptions.

Our project has been limited to studies of theHawaiian volcanos Mauna Loa and Kilauea,both located on the island of Hawaii. Thesevolcanos were chosen because (1) these volcanosare fairly active and erupt so frequently that wecan sample them as necessary, (2) we haveconvenient access to these volcanos through theHawaiian Volcanic Observatory, and (3) thebasaltic magma of Hawaiian volcanos has a lowviscosity, and eruptions usually occur as easilysampled lava fountains (volcanos with viscousmagmas erupt explosively and dangerously.).

To sample volcanic fumes, we modified thetreated filter pack sampling method used inatmospheric chemistry.21 The sampling systemconsists of a filter pack, a small 12-V DC pump,and a 12-V battery—all connected by flexibletubing. The filter packs contain a series of fivefilters, one of which is a Teflon particle filterthat collects 0.01-um-diam. particles veryefficiently. The remaining four are all base-treated filters designed to collect the acidic gasesin volcanic fumes. We chose 7LiOH as the basebecause it is strong enough to collect a weak acidsuch as SO2, is available in a relatively pureform to keep blank values down, and providesminimal interferences for instrumental neutronactivation analysis (INAA).

Kilauea volcano has been extremely activeover the past century; its most recent eruptionbegan in January 1983 and continues today.The first several years of this eruption we re-characterized by short periods chours to a few

days) of intense lava fbuntaining called episodes.Our first sampling mission to Kilauea was inNovember 1983 after episode 11. The next twosampling missions were conducted during andafter episodes 13 and 15 in January and Marchof 1984 (Kef. 22). In July and August 1985,we tried to collect samples during a completeeruption cycle. We began sampling several daysafter episode 33 and continued until the end ofepisode 35. The sampling was interrupted justbefore and during episode 34 when a hurricanethreatened the island. To complete our samplingof Kilauea, we returned in October 1985 tosample during lava fountaining in episode 38.

Mauna Loa began its first major eruptionin 35 yr by erupting in March 1984. The 2-dayeruption was characterized by low-level lavafountaining (<50 m). We sampled from 2 daysafter the eruption began through the end of theeruption and for several days after it ceased.23

Three different types of samples were takenfrom Mauna Loa and Kilauea: aircraft, activevent, and cooling vent gases. We used asampling device attached to the wing of theplane to collect gases from the plume duringfountaining activity. Active vent samples werecollected on the ground during lava fountainingor spattering. These samples were collected asclose to the vent as the activity would permit(usually <100 m). After the eruption ceased atMauna Loa and between episodes at Kilauea,we took cooling vent samples from fumes comingdirectly off cooling magmas.

The samples were analyzed by INAA at theLos Alamos Omega West reactor. Each filterunderwent a 30-s, 5-min., and 4-h irradiation,and element concentrations were determinedby Ge(Li) detectors from the resulting gammaactivity. Approximately 40 elements weredetermined in each sample.

After obtaining elemental data from oursamples, we determine whether the acidic gasesin the fumes were quantitatively collected.We examine the concentrations of the elementsfrom the major gases, sulfur (from SO2), andchlorine (from HCI), on the treated filters.If they have been quantitatively collected, theamounts of sulfer and chlorine will be higheston the first treated filter and progressivelylower on the following filters. In general, thefilters quantitatively collected acidic compoundsof chlorine, fluorine, bromine, arsenic, and

38 Isotope and Nuclear Chemistry Division Annual Kepor/ FY HitiS

Geochemistry and Environmental Cliemisiry

selenium. Sulfur dioxide was not alwaysquantitatively collected, especially on samplescollected for longer than 30 min.

Because samples were gathered at variousdistances from the vent, in fumes of varyingdensity, durir.g periods of differing eruptiveactivity, absolute elemental concentrations inthe samples are of limited value. Therefore, weuse ratios to look at changes in the compositionof the volcanic fumes with time and calculate anenrichment factor (EF). The EF is a measure ofan element's fractionation between the fumesand the magma relative to a reference element.We use bromine as the reference elementbecause it remains relatively constant for thedifferent sample types.

In the Mauna Loa and Kilauea samples,EFs are very similar within each sample type;however, there is a somewhat larger differencebetween sample types (see Fig. 3.6). The EFsare multiplied by 105 to make the lithophilicelements in the cooling vent samples close to 1.As can be seen here, the amount of ash in thesamples rises by a factor of 5 from cooling toactive vent samples, and by another factor of 5between active vent and aircraft samples.This clearly indicates that there is more ashin the fumes during an eruption than afterand more ash in the airborne plume than onthe ground—-just as we expected. The figurealso shows that many elements are highlyfractionated from the magma into the fumesbecause the volatiles (elements from copper tosulfur) a2-e enriched in the fumes by factors of

107

« «

10s

10*

103

10'

0

: • •

- , .

7A- C* U; T U V

Aaive Ver-:t

Cooling Venl

Aircraft

A. i

V / ^Ash »-

1

pJZ*4

Enriched Metals „and Voiatiies

* ' ** " F

11

10

S

rS~~ 7

'EO €3.

3 "A

2

1

0

/•—•** ACT m y

• / . _

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'/ .J* P03T-CRUPTIOW A

f i i <r—- m-B A02 0-i 0G

Refugm'3)

FIG. 3.6. Average EF by sample type for samples fromMauna Loa. Elements are ordered by increasing EFfor active vent samples.

FIG. 3.7. Plot of rhenium vs cadmium for allsamples collected at the 1984 Mauna Loa eruption.

100 to 10 000 000. Data for most volatilesand trace metals agree fairly well for the threesample types, and especially for active ventand aircraft samples. However, EFs for zinc,indium, and cadmium in cooling samplesdeviate from those in other samples by anorder of magnitude, which indicates changesin the chemistry of the fumes.

To examine the differences between sampletypes, we plotted concentrations of selectedelements. In Fig. 3.7, it is obvious that coolingvent samples are well separated from those ofthe active vent and aircraft samples. Differencesin eruptive and posteruptive fumes are largeand distinct enough to suggest the possibilityof distinguishing types of activity by their tracemetal ratios. Samples collected at a vent fromMauna Loa hours after the eruption had endedshow intermediate values between the eruptiveand noneruptive activity. By using trace mftalsto distinguish between types of activity, we maybe able to predict changes in volcanic activity.This is only a preliminary study of two volcanos;we plan to sample other basaltic and silicicvolcanos to discover if trace metals behavesimilarly in their fumes.

To understand the chemistry of volcanicfumes, we characterized emissions by theirelemental composition. Next we will examinethe speciation of these elements to discoverwhy changes in composition occur with eruptiveactivity. When we know the chemical speciesbeing released in the fumes, we can say moreabout the conditions under which the specieswere released.

Isotope awl Nuclear Chemistry Division Annual livport FY J9S8 39

AcHnide and Transition Metal Chemistry :

Overview

Determining the Redox Reactivity ofPlutonium(IV> Colloid

Synthesis and Properties of a New Class ofSynthetically Useful Precursors

Molecular Hydrogen Coordination toTransition Metals

Actinide and lYatwition Metal Chemistry

Actinide and Transition Metal ChemistryOverview

Alfred P. Sattelberger

Sevei'al INC Division programs in syntheticinorganic chemistry make important contri-butions to the Laboratory's missions and basicresearch and development programs. Ourresearch efforts include actinide coordinationand organometallic chemistry, ligand design,superoxidizer/superacid chemistry, transitionmetal-mediated reactions of small molecules,molecular hydrogen complexes, and materialschemistry.

Actinide chemistry is the cornerstone ofthe overall chemistry effort at Los Alamosand our programs in actinide chemistry providefundamental data on the synthesis, reactivity,and structure of actinide organometallic andcoordination complexes, ceramics, actinideseparations chemistry, and the behavior ofactinides under environmental conditionsand in nuclear waste isolation and storage.We have state-of-the-art facilities for synthe-sizing, handling, and characterizing a widevariety of actinide systems, including volatileearly actinide hexafluorides, aqueous phaseplutonium colloids, and air- and moisture-sensitive organometallic complexes.

In the actinide organometallic program,our current research focuses on the followingareas:

• Synthesis and characterization of newclasses of early actinide complexes thatcontain nonclassical ligands such asalkyls, silyls, amides, phosphides, andthiolates;

• Investigation of actinide-mediated smallmolecule chemistry, such as the insertionof carbon dioxide into actinide-alkyl,-amide, and -phosphide bonds;

• Synthesis and characterization ofactinide alkoxide and oxo/alkoxidecluster compounds that will be usefulmodels for aqueous-phase actinideoxo/hydroxide complexes relevant toenvironmental speciation;

• Development of low-temperature routes toknown and new solid-state actinidematerials from solution or the vaporphase.

Recent results from : * .aic researchprogram include (1) structural character-ization of the first thermalty stable uraniumalkyl complex, U[CH(SiMe3)2]3, (2) synthesisand structural characterization of UI3(THF).j—a valuable starting material for furtherexplorations of uranium(III) chemistry (seearticle by Clark and Sattelberger in thissection), and (3) preparation and x-ray structureof Me3SiNsU[N(SiMe3)2]3F, which is the firsturanium(VI) complex with a multiple bond toa main group element other than oxygen.

Actinide separations chemistry is a vitalcomponent of many INC-, MST-, and CLS-Division operations that support nationalsecurity and other programs such as plutoniumprocessing, nuclear weapons diagnostics, specialnuclear materials safeguards technology, andnuclear waste disposal. Major advances inseparations chemistry require a molecular-levelunderstanding of the way substrates selectivelybind to a receptor. The recent National ResearchCouncil report24 identifies six generic researchfrontiers where, "focused efforts could lead tomuch clearer insights into fundamentalprinciples and major opportunities for techno-logical innovation." The committee states:

"The most important generic researchgoal is to develop highly selectiveagents that can discriminate amongchemically similar species in a readilyreversible process. Research relevantto this goal focuses on understandingand generating separating agents withspecific chemical, physical, or biologicalinteractions at the molecular level."

The second-highest ranked area emphasizesthe development of agents to selectively removesolutes from dilute solutions. Our researchyields fundamental knowledge that is impoitantin both of these areas—especially when thesolutes of concern are actinide and lanthanideions. In recent work we have (1) developedextraction systems, based on soft donor atoms,that give a remarkable group separation of thetrivalent actinides from the trivalentlanthanides, (2) synthesized and characterizednew multidentate ligands with phosphoryl

42 Isotope and Nuclear Chemistry Division Annual Report FY

Actinide and Transition Metal Clutiiishy

and N-oxide functionality to bind actinides inhigh-acid media, (3) devised a templatesynthesis for and studied the coordinationproperties for a new octadentate Schiff basecryptand, and (4) examined macrocycliccomplexes of transition metals and lanthanidesas electrochemical fluoride sensors.

We anticipate that Los Alamos will play amajor role in the multibillion dollar moderni-zation and clean-up of nuclear productionfacilities throughout the country. Our researchprovides information that will be needed todevelop improved systems not only for actinideanalysis and processing, but also for remedia-tion of environmental actinide contamination.We are designing new ligand systems to enhanceseparation processes used for recovery and reuseof waste materials and to provide crucialinformation on actinide-ligand interactions.The economic advantage of reducing hazardouswaste is particularly apparent in the area ofnuclear materials processing. Because there aremany types of actinide-contaminated wastes andsites in the DOE complex, it will be necessary totailor separations chemistry to widely varyingconditions. INC Division will use its diverseexperience and expertise to respond to thesechallenges.

Another coordination chemistry project inINC Division is the study of plutonium oxides,hydroxides, and related compounds in near-neutral aqueous solution as a function of pH,Eh, ionic strength, and complexing ligandconcentration. This important informationis used to assess the potential for nuclidemigration in the environment and to separateheavy actinides. Solubility information may bethe determining factor in setting upper limitson the concentrations of actinides in naturalgroundwater systems. Therefore, it is extremelyimportant in designing studies of speciationeffects and radionuclide sorption by geologic media.

Much of our basic knowledge of actinidechemistry was established through studiesof actinide fluorine complexes. Recentbreakthroughs in research by INC and MSTDivisions will have significant impact in thisarea and will stimulate further progress. Inpart, these advances stem from our observationsthat dioxygen difluoride (FOOF) and kryptondifluoride ^KrF2J are capable of generating,from a wide variety of lower valent substrates,

the hexafluorides of uranium, neptunium, andplutonium at temperatures < 25'C No otherknown practical agents can carry out thesetransformations at appreciable rates attemperatures < 300°C!

In another major discovery, we found thatsuperacid media such as SbF5/HF and AsF5/HFare powerful complexing agents for virtually anyactinide substrate. Our results have demon-strated that the ability of superacids to convertactinide substrates that are normally highlyintractable, such as high fired oxides, metals,and high-impurity mixed oxides, is unmatchedby any other known class of compound.

Our experience with superoxidizers andsupersolvents leads us to believe that thereis tremendous potential for their use insynthesizing many new actinide compoundsthat have been unattainable because we lackedproper fluorinating or complexing agents.Our work with superacid media, particularlyin conjunction with superoxidzers, has openedup a new area of actinide fluorine chemistrythat has not only fundamental significancebut also important technological ramifications.

The Division's research in transition metalchemistry has focused on the basic chemistryof energy-related small molecules—primarilySO2 and H2—mediated by transition metalcomplexes. A fundamental understandingof.the cleavage of S=O and H-H bonds hasramifications in SO2 emissions control andwill provide new directions in catalysis.We have achieved the first example of homo-geneous catalytic reduction of SO2 to sulfur andH2O by hydrogen on the organometallicmolybdenum sulfide complex Cp'2Mo2S,|. (Cp =CsMes), and are investigating the mechanismsof this important reaction. In research related toH2 activation, our discovery of side-on bandingof H2 molecules to metals represents the firststable o-bond complex and serves as a prototypefor other c-bond activations, such as C-H bondsin hydrocarbons (see article by Kubas et al. inthis section). These complexes may be importantin catalysis, and we are studying the reactivityof M-H2 complexes toward protonation andisotopic exchange as well as the thermo-dynamics and kinetics of H2 reactions.

Isotope and Nuclear Chemistry Division Annual Report FY WHS 43

Actinide and Transition Metal Chemistry

Determining the Redox Reactivity ofPlutonium(IV) Colloid

David E. Morris, David E. Hobart,Thomas W. Newton* and P. D. Palmer

For many years we have known that aqueousplutonium(IV) converts to a colloidal speciesunder appropriate chemical conditions.25 Thisplutonium(IV) colloid is particularly importantin nuclear waste management and environ-mental contaminant arenas because we expect itwill be one of the dominant forms of plutoniumunder chemical conditions similar to those foundin typical groundwaters. However, despite thesignificance of this species, little is known aboutits chemical reactivity or its physical properties.As part of our ongoing programs with the USDepartment of Energy's Yucca Mountain Projectand the Office of Basic Energy Sciences, we areinvestigating the formation and stability of thisspecies as a function of solution conditions.26"27

Here we discuss preliminary results from ourmost recent studies of the chemical reactivity ofplutonium(IV) colloid toward oxidation andreduction processes.

Information on the redox reactivity ofplutonium(IV) colloid (the potentials at whichoxidation and reduction occur and the rates andmechanisms of these processes) is important aswe characterize this species. Redox reactionsmay represent viable mechanisms of colloiddegradation that produce dissolved ionic specieswith enhanced environmental mobility. Ourresults will also be valuable in defininggeneral reactivity patterns for the colloid andinterpreting other chemical kinetic phenomena.We may be able to use voltammetric redoxtechniques to study the colloid's physicalproperties; these data would be useful forcorroborating results from other techniques.

Investigations of the electrochemicalproperties of plutonium(IV) colloid (or anycolloidal material) present a keen challenge.The electrochemical behavior of dissolvedplutonium in its four readily accessible oxidationstates is well characterized28 and can beinterpreted within the framework of existingtheories of solution-phase thermodynamics andkinetics. In contrast, very few reports discussthe application of electrochemical methods toplutonium(IV) colloid studies. Presumably, thispaucity of data can be attributed to complexity

*Guest scientist with the Isotope and Nuclear ChemistryDivision.

of redox reactivity research in heterogeneousmedia such as colloidal suspensions.

Despite the anticipated complexity in theredox reactions of plutonium(IV) colloid, weexpect that the dominant electrochemicalpi'ocesses are reduction to a dissolvedplutonium(III) species and oxidation to adissolved Pu(VI)O2

2+ species, which may alsoinvolve a plutonium(V) species as anintermediate. Our initial experiments testedthese hypotheses. To determine the product ofthe reduction of plutonium(IV) colloid, we choseZn(Hg) amalgam, with a potential of-0.76 V vsthe normal hydrogen electrode (NHE), as areducing agent. We stirred a solution ofplutonium(IV) colloidal suspension in diluteperchloric acid in the presence of excess Zn(Hg)and monitored the course of the reactionspectrophotometrically. We readily identified theproduct spectrum as that of dissolved aquatedplutonium(III). This reduction reaction followedsimple first-order kinetics with a half-time of~40 min. In a related experiment, we used apotentiostatically controlled mercury cathodeand monitored the rate of reduction of thecolloid as a function of applied potential. In thiscase, we determined that a significant reductionrate occurs even at -0.46 V. The reactionappears to reach a maximum rate at —0.76 V,which is maintained at more negativepotentials. To determine the product ofplutonium(IV) colloid oxidation, we studied thereaction of a stirred solution of colloid in contactwith a platinum gauze anode. In this case, wefound no significant colloid oxidation takes placeuntil the potential reaches ~+1.6 V. The productof the oxidation was Pu(VI)O22+. We detected noPu(V)O2+ but cannot exclude its existence as ashort-lived intermediate in this reaction becausethe time scale of the assay was rather long.

Several years ago we investigated theoxidation of plutonium(IV) colloid by cerium(IV)in perchloric acid and found the reaction wasquite complicated. A recent report of similarstudies in nitric acid2** prompted us to revisitthese studies. We have now conductedexperiments in both nitric and perchloric acidsfor several colloid preparations that differ inparticle size. The potential of the cerium(IWIII)couple is —hi .6 V in nitric acid and —1-1.7 V inperchloric acid vs NHE. We monitored theoxidation reaction by measuring the spectro-photometric absorbance of the productPu(VI)O22+ peak near 830 nm. The initial colloidoxidation, quite fast in all cases, is faster in



nitric acid than in perchloric acid, and thereaction goes to completion only in nitric acid.In perchloric acid, the reaction is quenched after30 to 70% of the plutonium(IV) has reacted. Thisvai'iation in completion appears to depend onparticle size, acid concentration, and cerium(IV)concentration, but we have not yet found anyobvious trends. Figure 4.1 shows representativekinetic data for these experiments. Data fornitric acid appear to follow theoretical second-order kinetic behavior. This is very surprising;it suggests that the rate law is second-order inplutoniumdV) colloid concentration because theoxidant is present in large excess. We cannotformulate a simple mechanism that is consistentwith this finding. Data from experiments inperchloric acid do not appear to follow anysimple rate law. Our results are dramaticallydifferent from those of others who found a first-order dependence on colloid concentration innitric acid.29 We also note that small particle-size colloid samples react more rapidly than thelarge-particle size samples in nitric acid. Wehope to unravel these puzzling kinetic phenomena.

Our voltammetric studies used two standardtechniques: cyclic voltammetry and chrono-amperometry, both of which provide a muchshorter time-scale interrogation of the redoxreactions than the methods discussed above.We varied the potential of the indicatorelectrode (platinum for oxidation and mercuryfor reduction) and monitored the current flow,which is proportional to the rate of oxidation orreduction of the colloid. Because these

-o '0)oto

crT3

3

g 0.5

cro30_

c,go

Fra

o0

\ \

v» v .» \ •» V * .1 V %« V ».

» K\ X

0.5 1 1.5 2 2.5

Log [Time (min.)J

3 3.5

FIG. 4.1. In these Powell plots for the oxidation reactionof cerium(JV) with plutonium(FV) colloid, open circlesare data for a small-particle plutoniumdV) colloidsample in dilute nitric acid; filled circles are for alarge-particle sample in dilute perchloric acid. Thedashed line is the theoretical curve for a first-orderreaction; the solid line is the theoretical curve for asecond-order reaction.

experiments were done in dilute hydrochloricacid without stirring, diffusion and migrationwere the only means of delivering the colloid tothe electrode. We detected no oxidativevoltammetric activity for plutonium(IV) colloidby either technique. This suggests that thecolloid oxidation rate—even at potentials atwhich water is oxidized—is quite slow. Weobserved reductive voltammetric activity forplutonium(IV) colloid by both techniques;potentials ranged from -0.9 to 1.2 V. Thisvoltammetric behavior is distinctly differentfrom the usual behavior exhibited by dissolvedspecies. Figure 4.2 shows a series ofchrono-amperograms as a function of potential.These curves exhibit a current peak at timesgreater than t = 0 instead of the usual t"1/2

decay for t>0. We believe this novel behaviormay be attributable to the diffusion of apartially reduced colloid particle back tothe electrode surface for further reduction.

Our preliminary results for redox reactivity ofplutonium(IV) colloid reveal the anticipatedcomplexity in reactions for this species. Thepotentials at which the colloid is oxidized andreduced are well removed from those fordissolved plutonium(IV) and reflect the stabilityof the colloidal form of plutonium(IV). Althoughthese potentials are outside the range expectedunder normal environmental conditions,oxidation state stabilities of dissolved plutoniumspecies are strongly influenced by coordinationto environmentally ubiquitous complexants(such as carbonate ion), and similar effects mayexist for colloidal plutonium(IV). Our researchhas merely scratched the surface of thischallenging problem, and much additional workis needed before we can understand this system.

FIG. 4.2. Chronoamperograms for the small-partMeplutoniumdV) colloid in reduced dilute hydrochloricacid at a mercury vatho>ie. Potentials for curves Ithrough 4 are -1.20, -.".2o, -1.30, «nrf 1.35 V vs a Ag/AgClreference electrode.

Isotope and Nuclear Chemistry Division Annual iiepurt FY 19SS 45

Actinidc and 'lYansition Metal Chemistry

Syntheses and Properties of Lewis BaseAdducts of Uranium Triiodide: A NewClass of Synthetically Useful Precursors

David L. Clark and Alfred P. Sattelberger

It is interesting, from an historical perspective,that after some 50 years of synthetic actinideresearch, very little is known about the non-aqueous chemistry of tzivalent uz'anium.30

The paucity of molecular uranium(III)compounds is undoubtedly due to a lack ofsuitable starting materials. The binary uraniumtrihalides, UX3 (X = fluorine, chlorine, bromine,iodine), are polymeric solids that are insolublein common organic solvents and quiteunreactive. Uranium tetrachloride, UC14,dissolved in tetrahydrofuran (THF) can bereduced (with sodium amalgam, for example)to produce a sparingly soluble materialformulated as {UC13(THF))X (Ref. 31).The exact identity of the latter material isunknown, and its utility as a precursor touranium(III) compounds is limited.

Ten years ago, Andersen reported thatmonomeric U[N(SiMe3)2]3 could be synthe-sized from !UC13(THF)X] and sodiumbis(trimethylsilyl)amide [Eq. (1)]. More thanone product is present in the reaction solution,however, and the yield of U[N(SiMe3)2]3 isonly about 60%, based on UC14 (Ref. 31). Morerecently, we have prepared the first examplesof trivalent uranium aryloxide complexes fromreactions of 2,6-disubstituted phenols (HO-2,6-Me2C6H3, for example) with U[N(SiMe3)2]3

[Eq. (2)] (Ref. 32). Similar experimentsemploying aliphatic alcohols provide a mixtureof uranium(IV) products, which indicates thatsimple alcoholysis reactions can promoteoxidation of the uranium(III) center. Thissuggests that the best routes into uranium(III)chemistry will require reducing conditions andligand metathesis. Unfortunately, there are nowell-defined soluble uranium trihalide startingmaterials for the metathetical procedures.

THFUC13(THF)X + 3NaN(SiMe3)2

U[N(SiMe3)233 + 3NaCl

Hexane

It is well established that the stability ofhigher oxidation state transition metal andactinide halides decreases in the order:fluorine > chloi"ine > bromine > iodine. In thecase of uranium, all the tetrahalides are known,but the tetraiodide is thermally unstable anddecomposes slowly to uranium triiodide andiodine at room temperature. This tendency ofiodide ligands to favor the trivalent oxidationstate prompted us to search for a soluble formof uranium triiodide. We have discovered aseries of organic-solvent-soluble Lewis baseadducts of uranium triiodide that are easy toprepare; they serve as excellent precursors toa variety of new and known trivalent uraniumcompounds.

A slight excess of clean uranium turningsreacts with freshly sublimed elemental iodinein THF solution at 0°C to yield royal blueUI3(THF)4 (1) in -70% yield after 24 h[Eq. (3)]. Compound 1 can easily be preparedon a 100-g scale! This solution reaction is notspecific to THF solvent alone.

THFU +1.5 I2 > UI3(THF)4

0°C(3)

A slight excess of oxide-free uraniumturnings also reacts with iodine at 0°C in1,2-dimethoxyethane (dme) solution to giveUI3(dme)2 (2) as a light-purple microcrystallinepowder in 80% yield [Eq. (4)]. This reaction is,however, slower than the THF reaction andrequires 3 days for completion. In a similarmanner, with pyridine as solvent, we obtainblack microcrystalline Ul3(py)4 (3) in 80% yield[Eq. (5)] after 2 days of stirring.

dmeU + 1.5 I2 > UI3(dme)2 (4i

0cC

pyU + 1.5L, -> Ul3(py)4 1.0)

o°c

U[N(SiMe3)2l3 + 3ArOHU(OAr)3 + 3HN(SiMe3j2

Compounds 1-3 are exceedingly air- andmoisture-sensitive, and all are soluble in THF.Adducts 1 and 3 are also slightly soluble intoluene. Only one type of THF or pyridine ligandis observed in the 1H NMR spectra of 1 and o atroom temperature. The infrared spectra of 1 -3show absorption bands characteristic of the



coordinated ligands. For example, infraredabsorption bands at 1011, 853, and 833 cnv1

were observed for 1—indicative of coordinatedTHF—whereas 3 displayed the expected shiftfor the in-plane ring deformation of pyridinefrom 604 to 621 cm*1, which is consistent withcoordinated pyridine.

Single crystals of UI3(THF)4 were grown froma concentrated THF solution at -40°C, and thestructure was determined from x-ray diffractiondata collected at 23°C. In the solid state,Ul3(THF)4 exhibits a pentagonal bipyramidalcoordination geometry about the uranium atom,as shown in Fig. 4.3. Two iodide ligands occupyapical coordination sites with an avei*age U-Idistance of 3.111(2) A; the third iodide ligandlies in the equatorial plane with U-I = 3.167(2) A.All four THF ligands lie in the equatorial planewith an average U-0 distance of 2.52(1) A. TheI-U-I angles between equatorial and axial iodideligands average 94.25(5)°, forcing the the axialiodide ligands to bend away from the equatorialiodide ligand. The resulting Iax-U-Iax angle is171.30(5)°. Note that there are two types of THFligands in the equatorial plane: those proximalto the unique iodide ligand and those distal to it.This result is consistent with the proton NMR(nuclear magnetic resonance) spectrum,

provided there is a rapid interconversion ofseven-coordinate structures (pentagonalbipyramid <—> capped trigonal prism, forexample) on the NMR time scale that time-averages THF environments.

The UI3(THF)4 reacts cleanly at or belowroom temperature with sodium or potassiumalkoxides, amides, phosphides, cyclopent-adienides, etc., to give high yields of spectro-scopically pure trivalent uranium productswith concomitant loss of THF-insoluble Nalor KI (Fig. 4.4). Some of these compounds—U[N(SiMe3)2]3, (C6H5)3U(THF), andU(OAr)3(THF), for example—have beenreported in earlier work but never in theyields (essentially quantitative) observed in ourlaboratory. Others, such as (C5H5)Ul2(THF)3,are new and offer exciting opportunities forfurther explorations of uranium(III) chemistry.We anticipate that UI3(THF)4 will be anexcellent precursor to a host of otheruranium(III) complexes.

FIG. 4.3. This ORTEP drawing of theUI^(THF)^ molecule emphasizes thepentagonal plane. Selected bond distancesand angles: U-I(l) = 3.103(2) A; U-K2) = 3.167(2)A; U-I(3) = 3.119(2) A; U-O(l) = 2.48(1) A; U-O(2)= 2.51(1) A; UO(3) = 2.54(1) A; UO(4) = 2.56(1)A; I(l)-U-I(2) = 95.01(5) °; I(1)-V.I(3) = 171.30(5) °;O(l)-U-O(4) = 68.9(4)c; O(3)-U-O(4) = 71.4(5)°;O(3)-U-O(2) = 70.2(4)°; l(2)-U-Q<2) = 76.1(3)';I(2)-U-O(l) = 73.9(3) °.

FIG. 4.4. Some reactions ofUI3(THF>4. Abbreviations:Ar = 2,6-R2C6H3; tmeda = Me2NCH3CH2NMeg; dmpe =Me2PCH2CH2PMe2; Cp = CSH5; Pd = 2,-t-dimetkyl-pentadienyl.


Actinidc and 'transition Metal Chanistrv

Molecular Hydrogen Coordination toTransition Metals

Gregory J. Kubas, Robert R. Ryan,G. Rattan, K. Khalsa, and Juergen Eckert'

The coordination, or binding, of atoms ormolecules (ligands) to transition metals isperhaps the most important chemical reactionto life on earth. Photosynthesis, respiration, andmost catalytic and enzymatic processes wouldnot be possible without the unique bondingfeatures of the d-orbitals of the transitionmetals. The dynamic nature of metal-ligandbinding facilitates chemical transformationsthat otherwise either would not occur or wouldbe too slow to support life or industrialprocesses. Until recently, metals were knownto coordinate ligands in essentially two ways:(1) interaction of a metal orbital with either a"lone" electron pair or an empty orbital of oneligand atom (as in iron-oxygen binding inhemoglobin) or (2) interaction with the pi (K)orbitals of groups of ligand atoms such as thosein ethylene (Fig. 4.5). In the latter case, thedouble bond of Cr^CHg is side-on bound to themetal, and the metal "back donates" electronsinto empty antibonding n orbitals on carbon.

Our discovery of side-on coordination of an H2

molecule to tungsten complexes (Fig. 4.6) wasstartling, therefore, because dihydrogen doesnot have it orbitals or lone pairs available forbinding.33-34 Hence, we have established a newclass of stable metal-ligand binding, that ofsigma-bond coordination. In this interaction,two electrons are shared by three atoms (themetal and two hydrogen atoms), and thebonding is somewhat like that in n coordination:the H2 donates to an empty metal orbital andthe metal back donates to sigma-antibondingorbitals (a*) of H2 (Fig. 4.5). Intramolecularinteraction of C-H sigma bonds of ligandsalready bound to metals through other atomswas already known (as "agostic" binding35), butH2 binding is significant because it is strictlyinter molecular. No one had believed that suchbonding could be stable at room temperature.The H2 ligand is reversibly bound; that is, it isnot tightly held and freely dissociates if thecomplex is exposed to vacuum. Therefore, wewere quite interested in determining the metal-

H2 bond energy, and collaboration with CarlHoff at the University of Miami resulted in thefirst measurements of this important value.The heat of reaction of H2 with the coordina-tively unsaturated precursor W(CO)3(PCy;.{)2to form W(CO)3(PCy3)2(H2) (Cy = cyclohexyl)measured by solution calorimetry, is -10 kcal/mole.Because the precursor already had an intra-molecularly bound "agostic" C-H from acyclohexyl group,3*5 this energy representsthe additional energy of the metal-H2 bond.Assuming the tungsten-C-H interaction is atleast 10 kcal/mole, the heat of reaction of H2

with the metal center would be ~20 kcal/mole.If we compare this result with 30 to 40 kcal/molefor "normal" strong donor or it acceptor ligandssuch as carbon monoxide, dihydrogen appearsto be one of the most weakly bonded ligands.Nonetheless, the mtermolecular metal-H2

o-bond interaction is 10 kcal/mole stronger thanthe m^ramolecular C-H c-bond interaction.

We found the H2 bonding to tungsten isstronger than to molybdenum, which is also aGroup 6 metal. It is useful to make correlationswithin a particular group because the metalshave the same electronic configurations.However, we could not initially synthesizeanalogous H2 complexes of the first rowGroup 6 metal chromium by the route wehad used for the molybdenum and tungstenspecies. Hoff s modification37 in the precursordid lead to the synthesis of Cr(CO)3(PCy3)2;we showed by x-ray crystallography that itcontained the same agostic metal C-H inter-action found for the tungsten complex. Thisspecies did bind H2 but only under high

M - olefin M-H 2

;>c<;)

M - K - bondM-a - bond

P-LANSCE.

FIG. 4.5. Bonding models are shown here comparing theinteractions between n orbitals of an olefin (for example,ethylene) and metal orbitals to those for U2 -ainter-actions with a metal. Shaded lobes represent electron-filled orbifatsandarrotvsdepict 'backdonation."


Ar/inido and 'J)-ausitio/i Meial Chvmiairy

pressure (300 psi 1%). Thus, we know thechromium complex binds H2 even more weakly,which is consistent with lower basicity of first-row metals (weaker M —» \\~> donation).

The dihydrogen complexes can be viewedas arrested intermediates in the formation ofhydride complexes, which contain atomicallybound hydrogen. Our dihydrogen complexesexist in dynamic equilibrium with theirdihydride forms (-20%) in solution:

W(CO)3(P-;-Pr3)2(H2)« WH2(CO)3(P-/-Pr3)2.

We have carried out nuclear magneticresonance (NMR) studies of this process anddetermined that the thermodynamic parametersAH", AS", and AG° are 2, 3, and 1 kcal/mole,respectively. The activation energy was10 kcal/mole and the first-order rate constantwas 20 S"1. These values show tha'J there is littleenergy difference between dihydrogen anddihydride bonding—a surprising finding becauseit has been thought that metal-dihydrogen-interaction was only an unstable transient alongthe reaction coordinate towards hydrideformation.

Metal-H2 binding is probably the moststructurally dynamic metal-ligand systemknown. In addition to the above equilibrium,the bound H2 rapidly exchanges with free H2

and also undergoes isotopic exchange withdeuterium to give HD by an as yet undeter-mined mechanism that necessarily must invokeH-H bond cleavage. Because the H2 complex isalready coordinatively saturated, it is difficult toenvision how the D2 interacts with it to produceHD. The HD formation occurs even in solid-gasphases, and we are planning kinetic andmechanistic studies to determine whether wecan obtain evidence for intermediates.

Another important dynamic aspect is rapidhindered rotation of the H2 about the metal-H2

axis. We have carried out extensive neutronscattering studies of this phenomenon becauseby determining the energy barrier to rotationwe will obtain direct experimental informationabout the nature of metal-H2 bonding.Inelastic neutron scattering is an excellenttechnique here because the interaction ofneutrons with hydrogen nuclei is very sensitiveto large-angle motion of hydrogen. Experi-mental measurements were carried out at

both Los Alamos and the Institute Lauc-Langevin in Grenoble, France. The spectraobtained on LANL's Filter DifferenceSpectrometer are similar to vibrational spectraand show torsional (rotational) frequenciesat 300 to 400 im"1. Using these data,we foundthe calculated rotational barriers for severaldifferent tungsten, molybdenum, and ironcomplexes were 1.1 to 2.4 kcal/mole, which isgenerally much smaller than those calculatedfor metal-olefin rotation. For identical ligandsystems, the barrier depends on the metal,implying that the barrier is determinedprincipally by electronic interaction betweenmetal and H2. These bamers do have stericcomponents; that is, nonbonding interactionsof the H2 with other ligand atoms in closeproximity (Fig. 4.6). Molecular mechanicscalculations showed that these interactions aresmaller—0.6 to 1.4 kcal/mole for the tungstencomplexes. New theoretical calculations on themodel complex W(CO)3(PH3)2(H2) show that theelectronic component of the barrier should be~1.6 kal/mole. If we add the steric componentto the latter, we get values close to those fromneutron scattering, which lends experimentalsupport for-metal-to-H2 back donation in thebonding model. Therefore, cr-bond coordinationis somewhat similar to rc-bond coordination,except it is weaker because of the energies ofthe orbitals involved.

FIG. 4.6. This'ball and stick" model depictsthe crystallographically determined molecularstructure of W(CO)^P(isoCsH7)3]2(H2> <**d

shows H2 (blue) bound to the tungsten center(yellow). The proximity of the atoms of thephosphine group to the H-j is evident fatheratoms: carbon (black), hydrogen (white),oxygen (red), and phosphorus (yellow-orange)!.A CO ligand is obscured by the tungsten.

Isotope, and Nuclear Chemistry Division Annual liepvrt FY WSti 4{J

Materials Chemistry

Overview

Solution Routes to High-TemperatureCeramic Superconductors

Chemistry of Nitroalkanes and RelatedMolecules at High Pressure

Synthesis of New Quasi-One-DimensionalMixed-Valence Solids

Materials Chemistn1

Materials Chemistry Overview

Basil I. Swanson

The lack of suitable materials often limitsthe implementation of new, more sophisticatedapproaches designed to address problems indefense, energy, environment, communications,space, and other technology areas. To overcomethese limitations, it has become increasinglyimportant to synthesize and characterizesubstances tailored for particular applications.Chemistry provides an essential componentin our fundamental understanding of therelationship between microscopic and macro-scopic properties—vital information as wedevelop advanced materials with optimalproperties for specific purposes.

Materials chemistry research continues to,grow rapidly in INC Division as our capabilitiesin this area become more widely known andsour knowledge of probems and applications !increases. At present, the materials chemistryeffort is chiefly in Group INC-4, where scientistsemploy their capabilities in novel materialssynthesis and characterization to study anincreasing number of materials problems. •Materials research activities in other INCgroups are expected to grow as their expertisein analytical chemistry, process chemistry,chemical diagnostics, and isotopes is focused onproblems associated with advanced materials.1

For several years we have studied chemistryand materials behavior under extreme pressureand temperature conditions. One of ourprincipal motivations for this type of workis the need to develop a microscopic-levelunderstanding of how energetic materialsfunction. For example, we must understandand control the initiation of detonation of highexplosives and propellants so that we can use ]

these energetic materials more safely in avariety of defense and nondefense applications.A wide range of stimuli, including the impulsivepressure and temperature rise associated witha shock wave can initiate the detonation ofenergetic materials. Group INC-4's programcenters on the use of diamond anvil cells and awide variety of optical and structural probes tostudy molecular systems at high static pressureand temperature. Complementing this effort isa joint Group INC-4/M-9 collaboration that uses

spectroscopic methods to probe spociationbehind a shock wave. It is only throughcomplementary studies of this type thatwe can develop an understanding of thechemistry that occurs under shock loading.The article by Agnew et al. in this section providesan overview of one aspect of our research withmaterials under extreme conditions.

In response to the Laboratory's call forenhanced research on the new class of ceramichigh-Tc superconductors (HTS), some INCDivision scientists have redirected their effortsto address problems in characterization andsynthesis of these materials. One of theimportant unresolved issues associated withceramic HTS is the control of composition,structure, and material homogeneity. OurDivision's approach has been to develop solutionroutes to HTS films and bulk materials; theseroutes include sol-gel methods that use metalalkoxides and the synthesis of precursormolecules with idealized metal stoichiometries.Our researchers also have employed diffraction(x-ray and neutron) methods, opticalspectroscopy, and neutron activation analysisto characterize HTS materials. In particular,structural studies have been quite importantin helping to establish phase stabilities andto gain a better understanding of the solid statestructures of these materials. The article bySauer et. al. in this section describes our effortsto investigate HTS materials preparation.

Over the past three years,we have developeda research program in novel, electronicallyactive, low-dimensional materials. Thishighly multidisciplinary effort began with acollaboration between spectroscopists in GroupINC-4 and theorists in Group T-ll who wereinterested in nonlinear materials; it nowinvolves scientists from Groups INC-4, T-12,T-ll, P-10, and MEE-11. The materials ofimmediate interest are quasi-one-dimensional,mixed-valence solids for which a competitionbetween electron-electron forces and electron-phonon coupling controls the ground and localstate properties as well as macroscopicproperties such as conductance. These complexmaterials present new theoretical challengesthat require a combination of quantumchemistry, band theory, and many-bodymodeling to span from isolated metalcomplexes—which are the building blocksof these low-dimensional materials—to the


Materials Chemistry

extended interactions present in the solidstate. One of the program's objectives is tocharacterize and model these materials aswe chemically tune the competition betweenelectron-electron forces and electron-phononcoupling to optimize materials properties.We hope to develop a theoretical understandingof charge instabilities in these crystalline low-dimensional materials that we can also applyto many other important solids, including thenew ceramic HTS systems. Another objectiveis to synthesize new low-dimensional nonlinearmaterials for applications such as microscopicswitches, sensors, and nonlinear opticalmaterials. The article by Clark et al. in thissection presents recent results on the synthesisof an entirely new class of low-dimensionalmaterials that show great potential for tuningmaterials properties.

The future of materials chemistry researchin INC Division is exciting as new opportunitiescontinue to emerge in novel materials synthesis,modification, and characterization. Animportant frontier in materials science is thedetermination of reaction pathways requiredto turn individual inorganic, organometallic,and organic molecules into new materials thatwe will use to address specific applications.One promising area is the synthesis of precursormolecules for chemical vapor deposition (CVD)and chemical vapor impregnation (CVI) methodsthat will be used to prepare thin film metals andceramics. For example, new precursor moleculesused in CVD processes can lead to applicationssuch as the preparation of noncorrosive metalfilms for use as coatings for structural ceramics.We will also investigate new routes to ceramic-ceramic composites that employ volatileprecursor infiltration (CVI) into structuralceramics. These approaches to CVD and CVIrely on the synthesis of new molecules withappropriate physical properties and chemicalstoichiometries that mimic the final productmaterial. We will examine solution routes tometal-matrix composites and structuralceramics for conventional defense applications.Synthetic studies to create new precursormolecules must be complemented by studies todetermine reaction chemistries that will lead toother advanced materials. Materials processingchemistry also is required to take advancedmaterials from the research stage to thetechnology development stage.

Other areas of growth within materialschemistry include traditional solid statechemistry, materials diagnostics andcharacterization, materials processing, andinvestigations of ways to use our traditionalstrengths in isotope chemistry for materialsmodification. Our materials chemistry programsmust begin to combine all these elements intoan integrated approach that includes bothresearch and technology development. Forexample, frontier areas such as the new ceramicHTS require the input of solid state chemistryfor both materials synthesis and anunderstanding of structure/functionrelationships that are essential for correlatingcomposition and properties. In this area,materials characterization and new efforts inmaterials processing research are emerging asimportant activities for INC Division and theLaboratory. Characterization continues to be animportant aspect of materials research as doesINC Division's capability to address materialsproblems by using EXAFS, neutron activationanalysis, mass spectrometry, ion-microprobe,diffraction methods, and optical spectroscopy.

The Division's capabilities in the productionand use of stable and radioisotopes may alsofind several applications in materials research.Many materials use impurity doping of hostlattices or matrices to achieve desiredstructural, electronic, or optical properties.Solid state lasers, for example, rely on descretestates of impurities to achieve populationinversion in gain media. Doping with radioactiveisotopes could lead to molecular modification ofmaterials by radiation damage or annealingwith concomitant improvement in materialsproperties. The use of pure materials withselected isotopes also is important, as we haveshown by employing 12C in diamond films forenhanced heat transfer properties and 16O inPuO2 for application as a heat source.

We anticipate that the role of chemistryin materials research and development willexpand as requirements for new materials andcharacterization of materials behavior becomemore complex. INC Division will participate inmaterials design, synthesis, fabrication, andprocessing efforts that are directed toward abetter understanding and predictive capabilityfor materials behavior in programmaticapplications.

Isotope arid Nuclear Chemistry Division Annual Report FY 1988 53

Materials Chemistry

Solution Routes to High-TemperatureCeramic Superconductors

Nancy N. Sauer, Eduardo Garcia,Kenneth V. Salazar, and Robert R. Ryan

A wide range of technical applications requirethin films of the new high-temperature super-conductor YBa2Cu3O7. Although severalmethods, such as laser deposition or electronbeam evaporation, are available for depositingthese ceramic materials as thin films, theyrequire specialized equipment or facilities.38

In contrast, routes based on soluble precursorsthat can be spun or dipped into films appearattractive for a variety of reasons, including lowexpense, the ability to coat large, unusuallyshaped objects, and increased film homogeneityand purity. We are exploring two solution- basedroutes to superconducting films: sol-gelprocessing and synthesis of molecular precursorswith the desired 1:2:3 metal stoichiometry.In the sol-gel process, the controlled solutionhydrolysis of metal alkoxide compounds resultsin condensation of soluble polymeric species,which can then be spun to films or formed intobulk materials. Thermal degradation of thefilms or formed materials drives off organicIigands and produces the desired ceramicoxides.39 This method's versatility made it anexcellent choice for our investigations of solutionroutes to YBa2Cu3C>7 thin film preparation.

The following paragraphs describe syntheticand mechanistic studies we initiated for thisroute to thin films of YBa2Cu3O7, the physicalcharacterization of resultant thin films, and ourpreliminary efforts to adapt this method forfilms of bismuth-based superconductors.

To prepare precursor solutions for spinning thinfilms, we react a copper dimer, [(acac)Cu(OR)]2,with barium metal in 2-methoxyethanol in aninert atmosphere drybox. A redistribution reactionoccurs in which the acac ligand is transferred tobarium, producing (acac)Ba(OR) and formscopper alkoxide as an insoluble blue precipitate.

o2.5 (acac) Cu

acac- 2,4 pentanedioneR^ CH2CH2OCH3

• 2 B a ' « * 2 (acac)Ba (OR) +2 C J ( O R ) 2

01.5 (acac) Cu s ^Cu(acas)

0

After removing the insoluble copper alkoxideby filtration, we hydrolyze and add yttriumalkoxide to the resultant blue solution; thissolution is used for thin film deposition.Presumably, hydrolysis results in a soluble,condensed copper-barium alkoxide species,to which we add the yttrium alkoxide. Theseprecursor solutions have been used to depositYBa2Cu307 on Pt3 (Ref. 40).

For film preparation, we spin several coatsof precursor solution onto 0.25-in. SrTiO3 substrates.After each set of coats, we heat the films at250°C for 5 min to decompose the precursor andremove organic residues before additional coatsare deposited. To achieve complete coverage ofthe substrate, we apply multiple coats (30 to 50)of the precursor solution. We heat the filmsrapidly to 920°C in argon or nitrogen and holdat 920°C in an O2 atmosphere for 15 min toconvert the deposited material to the 1-2-3phase. A final oxygen anneal (2 h at 420°C) isnecessary to convert the insulating tetragonalphase, YBa2Cu3O6, to the orthorhombicsuperconducting phase YBa2Cu3O7.

We analyzed films prepared with this methodby resistivity, powder x-ray diffraction, Ruther-ford backscattering (for metal stoichiometry),and nuclear reaction analysis (to determinecarbon residue levels). Four-point-probe resist-ivity measurements show that the films undergoa superconducting transition at 85 K and havezero resistance at 65 K Figure 5.1 shows atypical plot of resistivity vs temperature forfilms prepared by this method. Both the widthof the superconducting transition (15 K) and thesmall slope of the resistance at temperatureshigher than Tc suggest that the sample may beoxygen deficient, a problem we can alleviate byincreasing the annealing time at 420^ . X-raypowder diffraction found only small amounts ofimpurity phases.

X-ray diffraction also gives us an under-standing of epitaxy, another key feature ofsuperconducting films. Aligning the super-conducting grains on the films substrate greatlyenhances the current carrying capacity of thefilm; thus it is very desirable to have methodsthat produce a high degree of alignment.Diffraction studies on our films indicate at least50% alignment of superconducting grains. Wehave yet to complete studies designed to assessthe current carrying capacity of these films.


Materials Chemistry

FIG. 5.1. Resistivity vs temperature plot for thin films ofYBa2Cu3O7.

Because this is a metal-organic route to thesuperconductor, we also were concerned aboutcarbon contamination of the films. Nuclearreaction analysis, however, found that onlysmall amounts of carbon (>0.1 at.%) werepresent. It is not clear what level of carbonthese films will tolerate before film qualitydeteriorates; therefore, we will investigateother alkoxides as synthetic precursors to films.In general, preliminary diagnostics on thesefilms did not identify any significant problemswith this sol-gel route. We have concluded thatthe low superconducting transition temperatureand the broad transition are manifestations ofthe films' thermal processing: we believe thatoptimizing the firing conditions will substan-tially improve the quality of these thin films.

To achieve a better understanding of thechemistry occurring in this process, we havebegun to isolate the intermediates at eachstage of this process and characterize themstructurally. In the initial reaction of[(acac)Cu(2-methoxyethoxide)]2 and bariummetal, we found that slow evaporation of2-methoxyethanol solutions [obtained afterseparation of the precipitated Cu(OR)2 (rxn 1)]produced large, dark-blue crystals suitable forx-ray crystal structure analysis. Figure 5.2shows the molecular structure for the isolatedcompound Ba2Cu2(acac)4(OR)4»2 HOR, whereR = CH2CH2OCH3. The metals are arranged ina diamond shape, in which two triply bridgingalkoxide ligands cap each face of the metalplane. Each of these alkoxides is further boundto a barium through the methoxy unit of themethoxymethanol.

The formation of this Ba2Cu2 cluster from asolution that contains a 2:3 ratio of barium tocopper suggests this compound is an inherentlystable unit. It may be suitable as a template forbuilding a molecular precursor cluster with thedesired 1:2:3 yttrium:barium:copper metalstoichiometry through reactions with yttriumand barium alkoxides.

The final segment of work on high-temperature superconductors involves ourrecent efforts in the area of bismuth alkoxidechemistry. We have just begun to explore thischemistry; if we are able to use bismuthalkoxides as molecular precursors tosuperconducting thin films, we must firstexamine the synthesis and structural chemistryof bismuth alkoxides. We will then be able toidentify appropriate precursors for a sol-gelroute to films of the bismuth superconductors.

In addition to our studies on bismuthalkoxides, we will continue to investigate themechanism of the solution process. Firingconditions will be varied to optimize the super-conducting transition as well as to increase theepitaxial growth of the superconducting grains.The Ba2Cu2 cluster will be used as a startingmaterial for cluster expansion reactions.Clusters resulting from these reactions, with thetarget YBa2Cu3 stoichiometry, will be used asmolecular precursor for films.

FIG. 5.2. Molecular tincture of Ba Cw(OR)4*2 HOR, h RCHCHOHand white * carbon.

BMtCwt s: 0XygCH


Materials Chemistry

Chemistry of Nitroalkanes and RelatedMolecules at High Pressure

Stephen F. Agnew, Basil I. Swanson,David Pinnick, Patrick Killough, andDouglas Eckhart

The chemistry that occurs under extremepressure (1 to 10 GPa or 10 000 to 100 000 timesatmospheric) is of interest to many diversedisciplines, including energetic materials,geochemistry, planetary physics, and novelmaterials development. Our research inmaterials at high pressure is primarily linkedto our need to understand the chemistryassociated with sensitivity and ignition ofenergetic materials.

We use diamond-anvil cells to generate veryhigh pressure (0.1 to 25 GPa) in a very smallamount of material (5 to 10 ug). Of course,it is difficult to obtain quantitative informationon such a small amount of material, and wehave needed to adapt our various spectroscopictechniques to analysze microscopic quantities.The techniques that we have used for thematerials described here are infrared absorp-tion, fluorescence (for the ruby emission usedas a pressure calibrant), and spontaneousRaman scattering.

What Have We Learned about High-Pressure Chemistry?Our studies have included several materials,including nitric oxide, dinitrogen tetroxide,nitrosyl chloride, and nitromethane, that havethe common chemical feature of nitrogen oxidefunctionality, which is ubiquitous amongenergetic materials. By determining the kindsof chemical transformations that occur at highpressure in these nitrogen oxides, we will gaina better understanding of the chemistry ofenergetic materials under similar conditions.We already know, for example, that reactionsinvolving negative volume changes areaccelerated with increasing pressure; whereasreactions that involve positive volume changesare disfavored with increasing pressure. Itfollows that statements can be made about theeffect of pressure on the rates of general classesof reactions. Dissociative reactions, on theone hand, are reactions that directly tradeintramolecular bonds for intermolecularinteractions and therefore involve positive

volume changes. Such reactions are disfavoredat high pressure because the solvent cage mustexpand around the reactant center as thereaction proceeds. This expansion is like apiston compressing a gas—it takes work orenergy to accomplish the task. That work is theenergy the reaction must expand as it proceeds,thereby changing the amount of activationenergy and slowing the reaction down. Forassociative reactions, the converse is true andreactions are accelerated with increasingpressure. Another reaction type involves anegative volume change that creates ions.Ionic materials are more dense than molecularmaterials; the long-range order of moleculessurrounding an ion-pair (electrostriction) leadsto -AV for solutions and, therefore, ionicreactions are expected to become stronglyfavored with increasing pressure. Finally thereare concerted bond-making, bond-breakingreactions that do not involve change in volumeand should not be pressure-dependent.

We studied the reaction of the NO dimer N2O2at high pressure and low temperature because itis a model for a simple high-explosive material.This molecule, a high explosive in the condensedphase, is expected to show reactions that arecharacteristic for the -NO group in the absenceof either hydrogen or carbon. The products of thereaction of N2O2 under static loading at 2.0 GPaand 160 K are N2O and N2O3. The reactionproceeds as a solid-solid reaction and isapparently nondisruptive. The implication isthat an intermediate is formed as

o\

C = Us

This intermediate results from an associativestep (-AV), even though the overall reaction hasno change in molecularity. Therefore, withincreasing pressure, the overall reaction isaccelerated, provided the second step releasessufficient energy. Even though this reactionreleases about one-half of the thermal energyexpected from N9O2 —> N2 + O2, the overalllack of change in molecularity suggests this isnot the initiation reaction for detonation, butrather a competing reaction. However, it ispossible that the intermediate is common toanother reaction branch leading more directlyto N2 and O2. We are trying to understand the


Materials Chemistry

stabilization of this intermediate by studyingthe reaction of NaO2 in liquid and solid kryptonsolutions at high pressure.

We have also studied the decomposition ofnitromethane at moderate temperature. Thisdecomposition ma3- produce both COQ and H2O,thereby evolving substantial thermal energy.Nitromethane is another simple high explosive,albeit an extremely insensitive one, and hasbeen used as a model for insensitive energeticmaterial. Under low pressure, nitromethaneonly decomposes at very high temperatures(250 to 350°C). At high pressure, nitromethanedecomposes at more moderate temperatures(120 to 150°C) to produce three different volatileproducts—N2O, CO2, and H2O—as well as asolid residue that has been identified as eitherammonium formate (NH^HCOO") orammonium oxalate. Figure 5.3 shows therelative amounts of volatile products as afunction of reaction pressure, and we proposethe following general reaction scheme.

1 A

! B1c

D

E

H3C-NO2 —> 1/2N2O + H2CO + 1/2H2O

H3C-NO2 —> C 0 2 + NH3

H2CO + NH 3 + H 2 0 -

N 2 0 + NH3 —> 3/2 N2

N 2 0 + H2CO —> N 2 +

-> NH4+ + HCOO- H

+ H2O + 1/2H2

CO2 + H 2

-21.0 kcal

-83.8 kcal

H H 2 -12.7 kcal

-76.8 kcal

-85.9 kcal

The branching reflected by reactions A and Bis presumably indicative of a common inter-mediate or transition state, which we suggest is

H2C-N H2C oX N /

H

This is the 2+2 adduct of formaldehyde andHNO. The HNO dimer

\, OH

N 0

I IO

O

IIN

O

N\

OH

is suspected as an intermediate in the well-known overall reaction that produces N2O andwater under gas phase and matrix isolatedconditions; we believe it is implicated in the N2Oproduction we also observe with nitromethanedecomposition. The lack of reaction in the liquid

at slightly lower pressure precludes the actualproduction of HNO, and therefore themechanism must be concerted bimolecular.

What general principles have we uncoveredthus far in our investigations of chemistry atvery high pressure? The expected increasingimportance of concerted and intermolecularreactions vs dissociative pathways is veryevident, and we have noted differences withgas phase decomposition mechanisms. At evenhigher pressure, the increased stability ofionic moieties is a further extension of thisphenomenon because ionic solids have muchhigher densities than their molecular counter-parts. Thus, in both N2O4 and ONC1 we havefound that only self-ionization chemistry occursat high pressure. For nitromethane, differentkinds of chemistry can and do occur, but an ionicchannel nevertheless does appear at highpressure and is strongly favored.

Future WorkA better understanding of the chemistry ofenergetic materials at high density will greatlyincrease our knowledge of the chemistry thatoccurs in important applications of propulsionand detonation. Our new knowledge is a directresult of incorporating novel high-pressuredevices—diamond-anvil cells—with state-of-the-art instrumentation involving microscopicanalyses from fast-fourier-transform infraredabsorption spectrometers, laser Ramanspectrometers, and UV-visible absorptionand laser-induced emission spectrometers.By studying the chemistry that occurs underunusual and extreme conditions, we will gaina better understanding of the processes thatsometimes dominate these capricious materials.

f l 7

IE r

eact

ed

P

0 !

Z 0.40§ 0.3

I 02-5 0.1

0.00 2 4 6 B 1

Pressure (GPa)0

FIG. 5.3. Relative amount* of volatile products m*a function of reaction pressure.


Afaterials Chemistry

The Synthesis of New Quasi-One-Dimensional Mixed Valence SolidsContaining DirutheniumTetracarboxylate Subunits

David L. Clark, Carol J. Burns,Alex J. Zozulin, Alfred P. Sattelberger,and Basil I. Swanson

For many years chemists have been intriguedby quasi-one-dimensional mixed-valence solidswith either alternating mononuclear (ML4

n+)or binuclear (L4M-ML4n+) metal complexes andhalide ions (X-) because they exhibit unusualelectronic properties Cfor example, see Ref. 41).These materials have recently been recognizedas prototypical, low-dimensional charge-density-wave (CDW) systems that provide models forcharge transfer instabilities in solids such asthe new class of ceramic high-temperaturesuperconductor. Over the past few years,Group LNC-4 has performed extensive spectro-scopic studies on platinum linear chaincomplexes, including [Pten2][Pten2X2](C104)4and K4[Pt2(P2O5H2)4X;]nH2O (whereX = Clor Br). These studies were invaluable as wedeveloped an understanding of ground andlocal state structures and their relation tomaterials properties in low-dimensional CDWsystems.42-43 Our work is part of a coordinatedexperimental and theoretical program to studylow-dimensional solids as they are tuned awayfrom the trapped-valence CDW limit and towarda valence-delocalized structure.

Our detailed electronic structure calculationsperformed on [Pt2(P2OgH2)4Cl]4- model com-pounds agree with our previous spectroscopicresults- they indicate that the unusual opticalproperties of these mixed-valence bimetallicchains are the result of a low-energy electronictransition, which corresponds to an electrontransfer between neighboring Pt2+ and Pt3+

sites along the chain axis.' In the terminologyof modern chemical band theory, this representsan optical transition between an occupied metal-metal a* band on Pt2+-Pt2+ centers and anunoccupied metal-metal c* band on Pt3+-Pt3+

centers—referred to as an intervalence chargetransfer (see the right side of Fig. 5.4). To under-stand the fundamental relationship between the

electronic structure of the constituent bimetalliccomplexes and the extent of valence deloca!i-zation, we initiated a synthetic program to"fine tune" the electronic properties of one-dimensional materials through systematicvariation in the electronic properties of themetal and ligand units within a linear chainsystem. We anticipate that in a mixed-valencesystem, the corresponding band gap betweenoccupied (M2+-M2+) and unoccupied (M3+-M3+jre* bands would be significantly smaller thanthe a* band gap (because of decreased overlap;;therefore, the electronic properties of the rnixed-valence linear chain material would be altered(see the left side of Fig. 5 A).

In our exploratory program to prepare one-dimensional linear chain materials, we usedRu2(O2CR)4 complexes as the bimetallic linearchain subunit. We expected Ru2(O2CR;4 com-plexes would be uniquely suited for preparingmixed-valence linear chain materials with aband gap between occupied and unoccupiedbands of it* symmetry like the o* gap in theplatinum chains.44

We prepared Ru2(O2CR)4 complexes by reflux-ing hydrogen-reduced methanolic "rutheniumblue" solutions with a stoichiometric amount ofcarboxylate anion [Eq. (1)], slightly modifyingthe procedure described in Ref. 45. By heatingthe bis(methanolatej adduct under vacuum at80°C [Eq. (2)], we easily removed the axialmethanol ligand. This process allows us toprepare nonligated Ru2(O2CR)4 complexes for

;t* band

IVCT f

o*band

• •

SomaMM

IVCT

• • I

'Information provided by D. L. Clark, C. M. Boyle, andP. J. Hay, Los Alamos National Laboratory (1989j.

FIG. 5.4. This qualitative drawing shows filled (solidblocks) and empty (shaded blocks) electronic bands of aand it* symmetry in one-dimensional linear chainmaterials. Corresponding c* and n* band orbitals appearbelow each band, and the arrwv between the filled andempty bands depicts the IVf IT optical transition.


Materials Chemistry

a series of R .where R = H, Me, Et, CF3, But,and Ph. The Ru2(O2CR)4 complexes undergoreversible one-electron oxidation in solution,and the oxidation potential varies as a functionof R. The facile oxidation of Ru2+ to Ru3+ isan important aspect of generating a mixed-valence linear chain material that is based ondiruthenium units. We now have a convenientmethod of "fine tuning" the electronic propertiesof new linear chain materials based on theRu2(O2CR)4 core.

"RuC!2" + 2 NaO2CR -> Ru2(O2CR)4(MeOH)2 + 2 NaCl (1)

Ru 2 (0 2CR) 4 (Me0H) 2 -* Ru2(O2CRj4 + 2 MeOH (2)

To provide a continuous bonding frameworkbetween diruthenium centers, we chose a seriesof aromatic bifunctional nitrogen donor ligandssuch as phenazine (PHZj, pyrazine (PZ),quinoxaline (QN), and 4,4'-bipyridine (BPY),which are illustrated in the lower portion ofFig. 5.5. These ligands not only possess anaromatic xc system with vacant n* orbitals, butare effective in mediating electron-exchangeinteractions between metal centers. To prepare1:1 pyrazine adducts, we stir, ed one equivalentof Ru2(O2CR)4 and pyrazine in methanol orTHF solution and isolated the resulting darkpurple microcrystalline powder by vacuumfiltration [Eq. (3)]. Using this method, wehave prepared a series of Ru2(O2CR)4'PZ)compounds, where R = H, Me, Et, CCF3, CMe3 ,and Ph. In the case of pyrazine, Ru2(O2CR)4

compounds are sufficiently Lewis acidic, but theacid-base reaction occurs so rapidly that wehave been unable to isolate single crystalssuitable for x-ray diffraction analysis, evenwhen we used diffusion techniques. We foundphenazine is a significantly weaker Lewis basetowards these systems—so weak that only inthe case of the very Lewis acidic Ru2(O2CCF3J4

could a 1:1 adduct be prepared [Eq. (4)].This reaction produces purple crystals ofRu2(O2CCF3)4(PHZ) when a saturated diethylether solution is cooled slowly.

We have planned a single-crystal x-raydiffraction study, and we expect that themolecular structure of the pyrazine andphenazine adducts will be a simple extensionof the structure obs.-rved for disubstitutedLewis base adducts Ru2^O2CRj4L2 (as observedfor linear chains based on dichromium

subunits). The expected chain structure ofRu2(O2CR)4L compounds is illustratedqualitatively in Fig. 5.5.

Ru2(O2CR)4(THF)2 + PZ -> R U 2 I O 2 C R ) 4 ( P Z J <3j

Ru2(O2CCF3 j4(THF)2 + PHZ -»Ru2(O2CCF3)4 'PHZ) <4)

The different reactivity observed for pyrazineand phenazine bases towards Ru^CC^CR^compounds strongly suggests that usingintermediate Lewis bases such as quinoxaline(QN) and 4,4-bipyridine (BPY) would allowus to isolate single crystals of a variety ofRugtOgCR^L linear chain complexes forspectroscopic and structural study. Afterthe chain assembly, we plan to oxidize thematerial through vapor-phase transportdoping—a technique used successfully todope organic conducting materials.

The complexes discussed above representthe first of a new class of materials that relyon jc* orbitals to establish the extended overlapthat controls valence-delocalization in low-dimensional mixed-valence solids. We will beemploying crystal structures and electronicabsorption spectra to identify new materialsthat show promise of optimal valence delocali-zation and electronic conduction. We will thenfurther characterize and use this informationto help develop new theoretical models of chargetransfer instabilities in low-dimensionalmaterials.

R R

R = H, Me, Et, Cf3, CMe3, Ph

N N

PZ PHZ

\ 7

ON BPY

FIG. 5.5. A qualitative drawing represents the molecularstructure of new one-dimensional linear chain materialsof formula RugfOvCIDfiL), where R and L are as listedbelow the chain.

Isvtope and Nuclear Clwmislry l)n ision Annual Report FY JUHfi

Nuclear Structure and Reaction*

Overview

Molybdenum-Technetium Solar NeutrinoExperiment

Using the TOFI Spectrometer to MeasureHalf-Lives of Exotic Nuclei

Fission and Multifragmentation fromNiobium Beam/Gold Target Collisions

Nuclear Structure and Reactions

Nuclear Structure and ReactionsOverview

Jerry B. Wilhelmy

Nuclear studies continue to be a major aspectof both the applied and research componentsof INC Division. The role of nuclear chemistry(and, for that matter, low-energy nuclear physicsin general) is rapidly changing. Traditionalareas of low-energy studies dealing withdetailed questions of nuclear structurephenomena are being deemphasized; emergingis a general attack on the more fundamentalaspects of the nucleus. This trend is evidentin the increasing world-wide emphasis placedin such areas as relativistic heavy-ion reactions,a field in which one goal is that of identifyingand studying the thermodynamics of quarkdeconfinement. The trend is also evident inthe construction of new facilities like theContinuing Electron Beam Accelerator Facilityand, possibly, the Kaon Accelerator and theAdvanced Hadron Facility to address limitingquestions associated with definitive tests ofthe "Standard" model. There is also increasingemphasis on expanded electro-weak studies,especially those relevant to tests of neutrinoproperties and other cosmological issues.

This is truly an exciting time for nuclearscience and one in which INC Division can be amajor contributor. Many of the experiments, inan operational sense, require very sophisticated,ultrasensitive analysis techniques. At INC,we are blessed with unsurpassed capabilitiesin ultrapure chemical processing of radioactiveand nonradioactive species, thermal andresonance ion mass spectrometry atdemonstrated sensitivity levels in the106 atom range, and extensive, automatedcounting facilities for all types of radioactivity.An organization with a traditionally strongmultidisciplinary flavor, we are able to use ourbroad nuclear capabilities to attack a wide rangeof problems, from weapons diagnostics andnuclear waste storage to geological impactstudies. The emphasis of nuclear science withinINC is also rapidly changing. To provide someinsight into the range of our efforts, this year wehave chosen to highlight three diverse areas:TOFI spectrometer studies of the nuclear masssurface for low-Z isotopes far removed fromstability; ongoing efforts in medium-energy

heavy ion reactions, which are probingthe limiting excitation energy regime ofconventional nuclear matter; and studies ofsolar neutrino emission through the use of atime-integrating geological probe associatedwith the inverse beta-decay process of neutrinocapture on molybdenum ore samples to producetechnetium isotopes.

Though these articles represent major effortswithin INC, they by no means constitute anexhaustive description of our Division'sactivities in this field. In low-energy studies,we have continued to develop helium jettransport systems that will produce copiousyelds of isotopes far from stability throughspallation and fission reactions at LAMPF;we have produced targets of 229Th for studiesof fission product dynamics; and we havestudied the systematics of neutron-capturegamma rays on separated calcium isotopesand thereby accurately determined reduceddecay probabilities for the important super-allowed transition in 42Sc. In the area ofmedium-energy theory, we are studying therole played by meson exchange for pionannihilation in low-energy double-chargeexchange reactions, and we are continuingto investigate the properties of nuclear mattercontaining bound eta mesons. In the heavy-ionreaction field, we have continued Monte-Carlointranuclear cascade studies to simulate ourmeasured reactions, and we have worked tounderstand and improve our large gas-detectorarrays for both medium-energy reaction studiesand possible application to accurate low-energyfission product determination. In fundamentalphysics studies, we have developed the requisiteprocedures for the mass spectrographicdetermination from molybdenite ores ofthe double-beta decay of 10oMo to 100Ru;we are attempting to establish theoreticallinks between pion double-charge exchangeand the double-beta decay process; and wehave joined a collaboration to perform real-time physical measurements on all flavor solarneutrinos. In support of other programmaticefforts, we are investigating the enhancedrelease of stored isomer energy in crystallinematerials and have begun a program to studynuclear isomer production in laser producedhigh-thermal environments.

From this description, it is obvious that we areinvolved in very diverse efforts in the nuclear


Nucloav Structure and Jicwiions

science field. To a point, this is a strength and anatural consequence of the evolving interests ofthe staff. However, we are a small number ofpractitioners, and too much diversity couldresult in isolation from overall Divisioninterests. Funding is always a concern.We have partial direct support from theOffice of High Energy and Nuclear Physics,some support from the internal InstitutionalSupporting Research and Developmentprogram, and some support from the WeaponsSupporting Research efforts; we are, to somedegree, subsidized by available INCdiscretionary funding. To help ameliorate boththe funding and diversity concerns, we havecollectively tri^d to identify and develop newresearch areas where we can make forefrontcontributions to science in general and ourorganization in particular. After consideringseveral alternatives, we felt our organizationaloperational strengths lay in the areas of ultra-sensitive analysis. This is certainly fortuitous,because many of the most challenging areas ofmodern nuclear science require such expertise.In a recent major embarcation, we formallyjoined (with others from Group P-3) theSudbury Neutrino Observatory collaboration.This second-generation solar neutrino detectionfacility will provide information on both theflavor and spectra of the neutrino distribution.This study represents a major advance beyondcurrent experiments that determine only theintegral yields of electron neutrino fluencies assampled by inverse beta-decay reactions.

Over the next few years, we expect that theTOFI effort will continue to emphasize high-precision measurements in the A ~40 region,and there will be a coupling of spectroscopiccapabilities to identify and study beta-delayedparticle emission of far off stability species.The technetium solar neutrino experiment isnearing completion and should provide insightinto the long-term stability of the solar neutrinospectrum. We will attempt reconfirmation of anyextracted number through follow-onexperiments of technetium extraction fromthe Henderson molybdenum ore body.We also hope to increase the level of supportthat our nuclear science endeavors provideto programmatic efforts. Stimulated emissionof isomeric nuclear energy has great scientificand practical importance, and initial steps inthat direction—through isomeric implantationin crystalline matrices—should be investigated.

The INC Division has certainly madesubstantial contributions to a wide rangeof nuclear studies and has served as a focalpoint of expertise for programmaticrequirements. We believe that the field israpidly changing and that by taking innovativesteps into emerging areas we can continue ourhigh-visibility contributions.

Isotope and Nuclear Chemistry Division Annual Report FY 1988 €3

Xuch'ar Structure and Reactio,

Molybdenum-TechnetiumSolar Neutrino Experiment

Kurt Wolfsberg, Donald J. Rokop, andNorman C. Schroeder

The chlorine solar neutrino experiment of RayDavis and co-workers in the Homestake Mine46

is one of the more famous experiments of recenttimes. Its objective is to measure the flux ofhigh-energy neutrinos produced by thermo-nuclear reactions in the core of the sun. Thistask is accomplished by measuring the 36Arproduced through neutrino capture on 37C1 ina large underground tank of perchloroethylene.The result of 2.07 SNU (solar neutrino units)(lO36 captures s"1 atom-1), agrees with initiallimits from the Kamiokande II detector butseriousfy conflicts with the standard solarmodel's prediction of 7.9-SNU (Ref. 47). Thediscrepancy, known as the "solar neutrinoproblem," has prompted numerous theoreticalstudies and several experiments—proposed,planned, or in progress—designed to explainproduction of neutrinos in the sun, their proper-ties, propagation to the earth, and detection.

Explanations for the discrepancy generallyfocus either on transformation of electronneutrinos to another type of neutrino (vacuumor matter-enhanced oscillations) or nonstandardsolar models that reduce the central temper-ature of the sun and the high-energy (principallythe 8B) neutrino flux. Some nonstandard modelspredict periodic mixing of the sun's core withcooler adjacent regions about every 200 Myr;these events stem from gravity-mode instabilityand result in decreased nuclear reaction ratesfor periods of ~3 Myr. It is suggested that suchphenomena account for glacial epoches and thepresent-day low 8B-neutrino flux.48 Thus,a possible solution to the neutrino problem isa mixing episode that occurred within the lastseveral million years; this possibility leads tothe question of long-term flux.

The answer must lie in a long-term history ofthe sun, and evidence can most likely be foundin the earth's geological record. Neutrinosinduce rare nuclear reactions, similar to thosein the Davis experiment, on all nuclides in theearth. For low-to-moderate energies, thereactions are simple inverse beta decays toground state or low-lying excited states of thedaughter nucleus; these inactions simplyincrease the nuclear charge by one unit. For

more energetic neutrinos, highly excited statesof the daughter nucleus can be produced toallow neutron emission. Neutrinos producedby galactic collapses may be energetic enoughto induce significant reactions of the lattertype. The first requirement for a geochemicalexperiment is a suitable parent-daughterpair. Because neutrino capture rates are~10"35 captures/target atom/s, a number ofvery stringent conditions must be satisfied.The daughter nuclide should be sufficientlylong-lived to integrate over the long time periodof interest. An ultrasensitive detection methodis essential because only 106 to 10s daughteratoms will be assayed. Detection of productatoms would be very difficult in the presence ofany stable nuclides of the same element. (Forexample, a 1-ppt abundance of a different andstable isotope of the product element in 1000 kgof target in the above case represents 6 x 1018

atoms that must be discriminated against inmeasurements of a few million atoms.) Thus, itis desirable to chose an element that has nostable isotopes.

Background effects from other nuclidesthrough natural radioactivities and cosmicradiation must be tolerable. This means that theore deposit must be at sufficient depth, uraniumand thorium concentrations must be low, andconcentrations of nearby elements that can betransformed into the nuclides of interest mustalso be low. The target element and the productnuclide must have remained geologicallyimmobile. We must know the age of the depositand the product nuclide. It is also necessary toknow or infer the cross section for neutrinocapture. Calculations involving Gamow-Tellerstrength distributions are model-dependent; thedistributions are measured by forward-angle(p,n) reaction. Finally, we must be able toseparate submicrogram quantities of theelement from the ore material: chemicalseparation factors of >1020 are required.

Our molybdenum-technetium solar neutrinoexperiment, conceived by Cowan andHaxton,48'49 is the only such geochemical studytoday. In samples of deeply buried molybdenumore, we will measure technetium isotopes thatare produced by 38Mo(v,e-)98Tc, 97Mo(v,e M97Tc,and 98Mo(v,e-n)97Tc reactions. The first reactionhas an effective threshold of 1.74 MeV, whichmeans that it is effectively sensitive to only 8Bneutrinos from the sun. The second reaction hasa lower threshold and can be induced by "Be


Nuclear Structure and Heart ions

neutrinos as well. The third reaction is sensitiveto both higher energy neutrinos from the sun(8B and hep) and high-energy neutrinos fromgalactic collapses. Haxton and Johnson50 calcu-lated that, for a rate of 0.09 supernovae peryear, 40% of the 97Tc signal may be caused bygalactic stellar collapses. The half-lives of 98Tcand 97Tc are 4.2 and 2.6 Myr, respectively; theabundances of 98Mo and 97Mo are 24 and 9.6%.We expect ~108 atoms of 98Tc in ~50 tons of themineral molybdenite, MoS2, at equilibrium.

The only deep molybdenite deposit minedcommercially is the Henderson ore body, locatedat a depth of 1130 to 1500 m in Red Mountain,Colorado (see Fig. 6.1). The AIvlAX corporationmines this ore, which is -0.5% molybdenite.Fortunately, the uranium concentration in themolybdenite mineral is only '.. .3 ppm, whichmakes background reactions tolerable for theproduction of 98Tc and perhaps for 97Tc. Ourtasks are to (1) chemically separate technetiumfrom thousands of tons of ore and (2) measure106 to 108 atoms of 98Tc and 97Tc, by massspectrometry. The abundance of "Tc, producedby n,y reaction on 98Mo, should be orders ofmagnitude greater than that of 98Tc. Theabsolute concentration of 99Tc in molybdenitecan be measured on a laboratory sample that isspiked with 97Tc tracer during dissolution.The known concentration of 99Tc is an internalyield monitor as we determine 98Tc and 97Tc.

The AMAX corporation has been extremelyhelpful in initial chemical separations—a process we could not do with our ownresources. We perform the rest of the chemistryat Los Alamos; details are provided in Ref. 51.

After a number of chemical purification steps,we produce an essentially massless sample thatcontains the technetium isotopes. Mass spectro-metric isotopic measurements of technetium aredifficult to achieve because thermal ionizationrequires low-volatility compounds and relativelylow ionization potentials. In most forms, techne-tium is very volatile, and its ionization potential,7.3 eV, is too high to achieve efficient ionizationby standard positive thermal ionization pro-cesses. There is an additional complicationbecause the most ubiquitous isobaric impurityis molybdenum, which has similar ionizationcharacteristics and atomic masses. To overcomethese difficulties, we developed a negativethermal ionization technique in which TCO4ions are produced by L^C^ ion enhancers with

high efficiency and no isobaric molybdenumbeams. (One of our filaments is shown inFig. 6.2.) Molybdenum is produced as the MoO;j"ion. Isobaric impurities contributed by theionization technique are measured at 6 x 105

atom equivalents of 96Tc, 97Tc, and 99Tc.Measurement limits on pure samples of 98Tcand 97Tc are ~106 atoms.

Using the material produced from roasting-10 tons of molybdenite, we chemically purifiedthe technicium and measured 99Tc in thesample. We are now attempting to make thefirst measurements of 98Tc and 97Tc.

FIG. 6.1. The Henderson ore body is buried 4260to 5000 m below the turnout of Red Mountain inColorado. (Reproduced by permission ofEconomic Geology.,*

FIG. 6.2. Chemical processing by the AMAXCorporation and by Los Alamos produces amassless sample that contains th* techneemmisotopes on a rhenium filament.

Isotope and Nuclear Chemiatry Division Annual Report FY 1U88

.Xuclcar Structure and Reaction.*

Using the TOFI Spectrometer toMeasure the Half-lives of Exotic Nuclei

David J. Vieira, Yi-Kyung. Kim, ^Paul L. Reeder,** Ray A. Warner,**Walter K. Hensley,'**Jail M. Wouters,K. E. Gunther Lobner," Zong-Yuan Zhou,"1

and V. Gordon Lind"

The oiiginal goal of the Time-of-Flight Isochronous(TOFI) spectrometer was to perform systematicdirect mass measurements for the wide varietyof neutron-rich nuclei produced at the LosAlamos Meson Physics Facility (LAMPF). TOFIhas achieved this goal52'53 and continues to helpus understand the nuclear mass surface throughadditional mass measurements. This articledescribes developments that allow us to use TOFIas a recoil tagging device to measure the half-life of several p-delayed neutron-emitting nuclei.

Figure 6.3 shows the experimental arrangementfor this new work. Neutron-rich nuclei are pro-duced by a high-intensity (1-mA) SOO-MeVproton beam when it strikes the 1.0-mg/cm2

natTh target located in the thin target/switchyardarea of the LAMPF accelerator. Many of thesereaction products recoil out of the target withenergies of ~3 MeV/amu and with little angularpi-eference. Some of these recoils are transportedto the entrance of the spectrometer by fourquadrupole triplets and a crude mass-to-charge(M/Q) prefilter. The TOFI spectrometer, whichconsists of four 81 integrated-function dipolemagnets, ii designed to be isochronous—thetime-of-flight for an ion passing through thespectrometer is independent of its velocity anddepends only on the M/Q ratio. Measurementsof the ion's energy and velocity uniquely definethe charge state. Several additional features ofTOFI make this system suitable for studyingexotic reaction products: (1) the transit timesare short (typically 1 us); (2) the acceptance isreasonably large (Q = 2.5 msr, 8(p/Q)/(p/Q) = 4%);and (3) the system is nondispersive overall,which means that all transmitted ions (bothunknown and known species) are concentratedin a small focal spot (20-mm <>).

To discriminate between isobaric members(that is, nuclei with the same mass number but

"Utah Slate University. Logan, Utah."Pacific Northwest Laboratory, Richland, Washington.1"University of Munich, Munich, Federal Republic of Germany.ttNanjing University, Nanjing, People's Republic of China.

different atomic number), we determine theatomic number (Z) of each recoiling ion from itsrate of energy loss, dE/dx. In this experiment,we have employed a passive uniform degrader(a stack of six 0.4-mg/cm2 nitrocellulose foils)placed at an intermediate focus position in thetransport line. By combining measurements ofthe ion's velocity before and after the degraderwith its mass as determined in TOFI, we cancalculate the energy lost in the degrader. We usea plot of this calculated energy loss us theaverage velocity (as shown in Fig. 6.4,), to obtainthe characteristic Z ridge lines indicative of theion's dE/dx. In this way, we determine theatomic number of each ion, mass independently;Z resolutions range from 1.4 to 2.0% (fwhm).These results are consistent with the fact thatour measurements are limited by fluctuations inthe energy loss process.54

Because Z identification was performed aheadof the spectrometer itself, we were able to placea large high-efficiency neutron counter, whichconsisted of 40 3He proportional tubes in apolyethylene moderated housing, around asingle silicon detector at the exit of TOFI. Thisdetector provides both the stop time for themass-to-charge measurement and the totalenergy needed to determine the charge state.We use the neutron counter to detect thesubsequent P-delayed neutron emission ofidentified neutron-rich reaction products.Because P-delayed neutron emission occurs onlyin the most neutron-rich nuclei accessible byTOFI, this decay signature proved valuable inselecting the exotic species from among the moreabundant but less neutron-rich species thatwere also implanted in the silicon detector.We measure the half-lives of these p-delayed

CP Degrader/ and CPV TOFI

ION

vi- ; M/Q

NeutronDelecior

FIG. 6.3. The experimental setup to tag each recoilaccording to its M, Z, and Q and to measure its half-life by delayed coincidence. CP = secondary-electron,micro-channel plate, fast-timing detectors. Time offlight is a measurement of the ion's velocity before thedegrader (vl), velocity after the degrader (v2), and themass-to-charge ratio.


Nuclear Structure and

'ns)

ocity

(ci

ge V

el

2>

2.8

2.6

2.4

2.2

2.0

1.8

-

1 t

7_6

41j

*

i

10

Z=8

1 ^

Z=10

*

s

t1

• 1 .

4

Energy

i

I

!30

loss

Z=12

"•. i . S

HI

'• \ 1

50 70

in degrader (MeV)

FIG. 6.4. A plot of the calculated energy loss in thedegrader [AE - M(vl2-v22)/2J vs the average velocity[vave = (vl+v2)/2] yields the characteristic Z ridge linesindicative of the ion's stopping power.

neutron-emitting nuclei by a delayedcoincidence technique in which both the ionarrival times and the delayed neutron times arerecorded by a free-running, common clock.

Decay curves, such as those in Fig. 6.5, areobtained by producing time difference histogramsbetween M-, Z-, and Q-gated ion start eventsand all subsequent neutron stop events thatoccur within 1 s after the ion arrival time.*55 Alldecay curve data can be decomposed into an expo-nential decay component and a chance coinci-dence background component that is slightlytime dependent. This fairly large backgroundarises because (1) other delayed neutron emittersare continuously implanted in the stop detector,or (2) neutrons arise from sources outside the

a)

detector, such as neutrons produced directly bythe prittiary beam. We use 1:3B, which has anegligible delayed neutron emission probability(Pn = 0.3%), to determine the time-dependentshape of the background. The absolute magni-tude of this background is determined from the125-s integrated count rate measured tor eachparticular species of interest. We subtract thisnormalized background point by point to obtainthe net decay curve data from which we are ableto extract the half-life of the nuclide of interest.

During a proof-of-principle experiment, wedetermined the half-lives of 11 nuclei rangingfrom 9>1:lLi to 25F (Ref. 56). Our measurementsagreed well with those reported in the literaturefor nine nuclei. We are reporting the half-lives of21N (T1/2 = 170 (±33) ms) and 25F (T1/2 = 60(±30) ms) here for the first time. When we examinethe shell model calculations of Wildenthal57 andBrown* and the gross theory of (i-decaypredictions of Tachibana,58 our results showthat the half-life of 25F was well predicted, butthe half-life of 21N is 3 to 4 times longer thanexpected from theory. Further studies of 21N areneeded to explain this discrepancy.

This work represents the first use of the TOFIspectrometer as a recoil tagging device tofacilitate the decay characterization of exoticnuclei. We have suggested a passive degrader/velocity difference approach to determine theatomic number of the recoil and have measuredthe half-lives of several P-delayed neutron-emitting nuclei. We are planning other experi-ments with TOFI in this mode to measureadditional half-lives and to search for unknownisomeric states that could complicate theextraction of ground-state masses.

10000

9Li T(V2)=17l tnms

b)100i

c)

21N 7(1.21 = 170 JS3i100

21TO

tr

i

25F

200 400 600 800

Time (ms)

0 200 400 600 800 1000

Time (ms)

0 200 400 600 800 1000

Time (ms)

'Information received from B. A. Brown,Michigan State University (December 1988).

FIG. 6.5. Time difference histograms for (a) 9U, (b) *'N, and (c) 2SF.Open squares = total counts; filled squares = normalizedbackground counts (based on '"%>. Points with error bars = netcounts. Solid line = half-life determined from fit to net coMHfx.

Isotope and Nuclear Chemistry Dhision Annual Report FY J988 <i7


Fission and Multifragmentation fromNiobium Beam/Gold Target Collisions

Marieluise Begemann-Blaich,Thomas Blaich, Malcolm Fowler,and Jerry Wilhelmy*

Heavy-ion collisions with incident energiesbetween 20 and 200 MeV/A are considered tobe in a transition region between (1) collisionsat low energies, which are dominated by the meannuclear field of all nucleons, and (2) collisions athigh energies, which are dominated by the inter-action of individual nucleons. Therefore, thisregion should be marked by changes in themechanism for momentum transfer and energydeposition; it may show new decay modes—likemultifragmentation—and give us insight intothe defining conditions when a nucleus goesfrom a composite, cooperative, collective bodyto a mere spatially correlated ensemble ofindividual nucleons. We can obtain informationabout such an excited system from the relativeprobabilities for fission and particle evaporationand from the production probability for particleswith element number Z between 2 and 15—theso called intermediate-mass fragments (IMF).To investigate in detail, we studied, with highgeometrical detection efficiency, the reactionproducts formed in the collision between 50-, 75-,and 100-MeV/A niobium beams and gold targets.

Using the "Pagoda" detector system,59 weperformed the experiment at the low-energybeam line of the Lawrence Berkeley LaboratoryBeValac accelerator. The system consists of aneight-fold array of gas detectors, which arebacked by 54 fast-slow plastic phoswhichscintillators, and has, at forward angles, a34-element hodoscope (Fig. 6.6a). This combi-nation of detectors has a wide dynamic rangeresponse—it allows us to detect particlesranging from 200-MeV protons to slowly movingtarget residues. In earlier work we showed thatthe relative production probability for IMF israther high, but at that time, our experimentalsetup was not optimized to study this massregion.60 We have since improved our gasdetectors by adding a low-pressure dEproportional counter between the two existing

position-sensitive multiwire planes used todefine the time-of-flight region. The proportionaldetector gives a linear signal that is dependenton the energy loss of the transversing particle.Thus each gas detector gives us three signals forparticle identification: the time of flight betweenthe two multiwires, the dE signal from the frontproportional region, and an energy signal fromthe back ion chamber. In a plot of the front-ionchamber signal vs the time-of-flight, data areclearly separable into three generic classes offragments: heavy target-like residues, fissionfragments, and IMF, in which the separated Zlines between Z = 2 toZ = 10 can easily beidentified.

One of our most important projects this yearwas the calibration of the front proportionalchamber. This effort has resulted in an algorithmto extract che element number and primordialfragment velocity of all detected particles. Ourfirst plan was to calculate the energy loss indifferent parts of the detector and the time offlight by using the DONNA or ZIEGLER dE/dxcomputer codes. To compare these calculationswith experimental data, we used the Los AlamosIon Beam Facility to scatter a variety of heavyion beams (from carbon up to iodine) at energies

*In a consortium with staff members from LawrenceLivermore National Laboratory, Lawrence BerkeleyLaboratory* Argonne National Laboratory, and theWeizmann Institute, Israel.

Scale (in.)

0 5 10 1520

A E-E PtiosmctlTelescope Array

lonza'tonChamber

PressureProptoponwnai

MtVPCIBctTtKiecm)

FIG. 6.6. (a) Ibp schematic view of the "Pagoda"detectorsystem; (b) side representation of one of the eight detectorarray elements.



between 0.5 and 5 MeV/A on different targets(from titanium up to gold). At these energies,the scattering process is Rutherford, andtherefore we obtained energy and time-of-flightcalibrations for both the beam particles and thetarget recoils. Comparisons with the energy losscalculations showed a large discrepancy—whichis not understood—for both dE/dx codes used inour analysis. The detector response for twodifferent particles depositing the same amountof energy is not independent of the elementnumber, and this means we must use an ion-dependent calibration procedure. We havebeen able to couple these extensive empiricalcalibration measurements and the easilyidentified Z lines in the niobium/gold run toproduce an algorithm that extracts the physicalquantities Z and velocity from the measuredtime of flight and energy-loss signals indepen-dent of any theoretical dE/dx code (Fig. 6.7).

The Z identification is possible for particleswith incident energies between 0.5 and 2.7 MeV/Aand for Z smaller than 48. For light particleswith incident energies higher than 2.7 MeV/A,the resolution of the front-ion chamber is not, byitself, sufficient to extract the element numberfrom these signals. However, by combining thesedata with information from the back-ion

FIG. 6.7. Two-dimensional correlated data betweenthe fragment time of flight and the signalamplitude in the front proportional region.HR = heavy-element target-like residues; FF =fission fragments; and IMF = intermediate-massfragments. Signal intensity increases from blue togreen to yellow to red data points, as shown here.

chamber and/or the phoswhich detectors, weshould be able to identify the fast particles,which represent a significant portion oftotal fragment yield. For heavier nuclei, wedistinguish only between fission fragments andresidues, but we have velocity informationover a very wide range from 0.02 to 2.0 MeV/A.

We tested the new algorithm by analyzingfission fragments from a 252Cf calibrationsource and were able to accurately reproducethe known mean values for both Z and velocitydistributions. We applied this method to theexperimental data to extract Z and velocitydistributions for fragments produced in the50-, 75-, and 100- MeV/A niobium/gold collisions.We have concentrated on the low-energy portionof the fragment distribution; that is, on incidentenergies smaller than 2.7 MeV/A. The Z distri-bution of all detected single events as a functionof the beam energy is shown in Fig. 6.8. For allthree energies, the production probability forIMF, compared with the production probabilityfor fission or fission-like fragments, is fairly highand increases with increasing beam energy. Inthe next step, we will study the coincidence of agas detector module with any other detector.Because our geometric coverage is reasonablyhigh, we have a large yield of correlated eventsand expect that studies of the emissioncorrelations will provide both new insight intothe IMF production mechanism and informationon the multifragmentation process.

its)

rary

un

(arb

it

N

•a

10000

1000

400

_.

—*

I ' " " I - '

0 10 20

Z30 40

FIG.6.8. Observed yields of element* for the threeexperimental energies studied: SO (solid line), 75 (dmshedline), and 100 (dotted line) MeV/A niobimm projectiles. Thedata have been normalized in the fission product regionand show a relative enhancement of IMF «ur the remctionenergy is increased.

Isotope and Xuctsar Chemistry Division Annual Report FY 1988 €9

Division Facilities and Laboratories

Division Facilities and Laboratories

Omega West Reactor

ICON Facility

Facilities and Laboratories

INC-Division Facilities and Laboratories

Merle E. Bunker

In addition to the Omega West Reactor andthe ICONS Facility, which are described in thearticles immediately following, INC Division ispro i ofthese state-of-the-art laboratories andfacilities.

Advanced Radiochemical WeaponsDiagnostics FacilityThis facility, which occupies a new 10 000-ft2

building, was designed to minimize limitationsthat environmental factors impose on theaccuracy, precision, and sensitivity of isotoperatio measurements used in weapons testdiagnostics. The facility includes 11 chemistryand 7 instrument laboratories that are designedand operated to provide a particulate-freeenvironment in which to prepare samples andmeasure isotope ratios by mass spectrometry.The clean laboratories are constructed ofparticulate-free, corrosion-resistant materials.Critical work spaces are bathed in class-100filtered air, and the air flow is designed tominimize cross contamination between workareas. The instrument labs are shielded fromexternal electrical interferences, and theinstruments themselves are powered by isolatedmotor generators. The building currently housesfour single-stage, one double-stage, and onetriple-stage thermal-ionization massspectrometers. Another section of the facilitycontains a laboratory for measuring isotoperatios in noble gases. In a separate building,we also have in operation two large 1.5-m radiusmagnetic-sector isotope separators: one of 55°and one of 90=. These separators can be operatedat beam currents up to 50 mA. An additional126°, 1.46-m radius instrument is underconstruction.

In addition to work associated with nuclearweapons tests, the above laboratories areused for experiments in solar physics, thegeosciences, biology, and atmospheric science.

Counting Room LaboratoryThe Data Acquisition Section of Group INC-11maintains a large counting laboratory thatcontains a wide variety of calibrated detectorsystems for quantitatively determining theabsolute abundance of selected radioactive

nuclides. These detector systems include alpha,beta, gamma-ray, x-ray, and fission detectors aswell as a computer-based data acquisitionsystem and software for the collection andanalysis of the resulting data. We are currentlyinvolved in an extensive upgrade andautomation effort to increase the overallreliability of the various detector systems.We are also conducting research on backgroundreduction, gas-filled proportional counterimprovements, and new detector systems.

Medical Radioisotope Production Facilityat LAMPF and Hot Cells at TechnicalArea 48The Medical Radioisotopes Research section ofGroup INC-11 operates the Isotope ProductionFacility at the Los Alamos Meson Physics Facility(LAMPF), where up to 9 targets are simultan-eously irradiated in one of the most intenseaccelerator beams in the world (800 MeV,1.1 mA). These targets are highly radioactive(>100 000 Rem) when removed from the LAMPFbeam and therefore are processed in theextensive hot cell facilitiesat Technical Area 48.The latter facilities consist of 13 cells, each with18-in. lead glass windows and high-densityconcrete walls for shielding. These facilitiesmake it possible for the program to serve as anational resource for radioisotopes that are usedin nuclear medicine and biomedical research. Ofthe more than 30 radioisotopes in current use bythe medical profession, -15 are produced onlyhere at Los Alamos.

Single-Crystal X-Ray Diffraction FacilityGroup INC-4 maintains and operates a single-crystal x-raj' diffraction capability that is uniquewithin the Laboratory. The facility currentlyconsists of three automated single-crystaldiffractometers with the capability of datacollection at temperatures between -160 and1000°C. Data collection capabilities at highpressures (to 300 kbar) are also available.A variety of structure solution packages aremaintained, including the LANL systemTEXRAY and another package developed atthe University of California, Los Angeles.Both precession and Weissenberg camerasare used. An effort has been made to developa facility that is user friendly to knowledgeablebut nonexpert structural chemists. Currentoutput is 50 to 60 crystal structures/yr;maximum capability is -150. We providesupport for basic and appjicd research programs



in the areas of high explosives, small-moleculeactivation, actinide and fluorine chemistry, andseveral other molecular design projects.

Condensed Matter Spectroscopy FacilityGroup INC-4 operates and maintains anextensive optical spectroscopy facility in openlaboratories at Technical Area 21. Theinstrumentation includes several spectro-meters for spontaneous and resonanceRaman scattering, FT-Raman studies, infraredabsorption, electronic absorption and emissionmeasurements, photoaccoustic spectroscopy, andtransient Raman and electronic absorptionspectroscopy on the nanosecond time scale.Specialized equipment is also available forvariable temperature (4 to 600 K) and pressure(0 to 30.0 GPa), ultraviolet and near-IRresonance Raman, and ultrahigh resolutionFTIR studies. The facility supports basic andapplied research programs in energeticmaterials, photophysics and photodynamics,materials research, bioinorganic chemistry,geochemistry, and environmental chemistry.The condensed matter spectroscopy facility iscurrently used by scientists throughout theLaboratory and at several universities.

Classified Radiochemistry DocumentRepositoryThe Division's 40-yr accumulation of classifieddocuments is held in a repository maintainedby Group INC-11. The current estimate ofaccountable items is in excess of 50 000.In FY 1989, these documents will be movedto a newly constructed 1200-ft2 vault atTechnical Area 48 that will house a high-density mobile storage system with nearly450 linear feet of storage shelves, a computerroom for the Group INC-11 classified VAX11/780 (INCDP2) computer system, twoworkrooms, and an office area for the documentcustodian. To track the 50 000 documents, the-100 monthly send/receive transactions, and thethousands of other document control actions,we maintain a bar-code enhanced DATATRIEVEVAX/VMS data base on the INCDP2 system.This vault facility is the LANL historic resourcefor all weapons radiochemical diagnostics dataand associated test performance evaluations.

Division-Wide Computer NetworksGroup INC-11 sponsors a Division-widecomputing system in the open environmentand a smaller secure network for classifiedcomputations, data base management, anddocument preparation and control.The extensive open system is a distributedprocessor on the Laboratory IntegratedComputer Network (ICN) and permitsauthorized users to access more than 500other nodes on the ICN as well as all majoropen computing facilities at LANL's CentralComputer Facility. The most recent additionto our system, a VAX 8700 computer, networksmost of the Division's computing resourcesinto a cluster named MAGIC. This cluster nowallows user access from nearly 200 terminals to5 VAX computers of various sizes, a disk clustertotaling 10.8 gigabytes of memory for programand data storage, and 10 laser printers.In FY 1989, most of MAGIC's componentswill be consolidated in one location in BuildingRC-1 at Technical Area 48; the secure systemwill be relocated to the vault in the new RC-1Data Wing addition.

Time-of-Flight Isochronous (TOFI)SpectrometerThe TOFI spectrometer and its associatedtransport line is a facility designed to measurethe masses of energetic, recoiling nuclearreaction products. The TOFI facility is sitedat the Los Alamos Meson Physics Facility(LAMPF) to take advantage of the high yieldsof exotic light nuclei that are produced ininteractions of the intense 800-MeV protonbeam with heavy- and medium-mass targets.From measurements of the recoil's transit timethrough the spectrometer, we can make directmass measurements with precisions of 100 to1000 keV—depending on production rates.To date, we have measured the masses of 28neutron-rich nuclei that range from u L i to 37P.Recent improvements in the detection systemhave also allowed us to use TOFI as a fast-recoiltagging device that facilitates the gross decay-property characterization for many of theseexotic species.

Isotope and Nuclear Chemistry Division Annual Report FY 1S88 73


Omega West Reactor

Terry W. Smith, Gerald F. Ramsey,Michael M. Minor, Sammy R. Garcia,Keith H. Abel, and Merle E. Bunker

The Omega West Reactor (OWR), operated byGroup INC-5, is the only research reactor at LosAlamos. Its main purpose is to provide LosAlamos experimenters and scientists from otherlaboratories with an intense steady-state flux ofthermal and epithermal neutrons. The reactor isnormally operated at a thermal power level of8 MW, 7,5 h per day, 5 days per week. At 8 MW,the thermal-neutron flux in the core is 9 x 1013

neutrons/cm2-s, and the "fast" flux (> 0.1 MeV)is 5.6 x 1013 neutrons/cm2s. Extending awayfrom the core is a 5 by 5 by 7.5-ft graphiteregion (see Fig. 7.1), known as a thermalcolumn, which slows the fast fission neutronsfrom the core to thermal energies. Most sampleirradiations are carried out in this thermalcolumn. Numerous beam tubes, pneumaticrabbit systems, and removable graphite"stringers" provide access to the OWR'sneutron flux and allow several experimentsand irradiations to proceed simultaneously.

The reactor facilities are used for a widevariety of research activities, includingradioisotope production, neutron-diffractionand neutron-transmission experiments, in-coreirradiation of instrumented devices, neutronradiography of assemblies, neutron-captureprompt-gamma-ray studies, neutron cross-section measurements, radiation damage

6" ThroughPorts

12" SquarePorts

6" Beam Portswith Shutten

6" BeamPorts

Heavy Concrete,Shield

FIG. 7.1. Horizontal cross section of the OWR.

experiments, and neutron-activation trace-element assay measurements. Data on experi-ments other than irradiations performed at theOWR during FY 1988 are shown in Table 7.1.The total number of experiment hours (3649)exceeds by a factor of 2 the average valuerecorded over the 5 previous years. This largeincrease resulted mainly from expansion ofwork on thermal cross sections by the Subatomicand Research Applications Group (P-3), studiesof tritium storage devices by the WeaponSubsystems Group (WX-5), capture gamma-ray measurements by the Research ReactorGroup (INC-5), and high-level gamma-rayirradiation of explosives for the ExplosivesTechnology Group (M-l). A large fraction ofthe experimental work done at the OWR isin support of the weapons program.

The largest single use of the reactor is forneutron irradiation of materials, which isusually done to induce radioactivity in thesamples but, in some cases, is done to causephysical changes in the materials. In the lattercategory, recent examples include fast-neutronirradiations of both low- and high-temperaturesuperconductors by the Physical MetallurgyGroup (MST-5) to determine the effect suchbombardment has on the conduction propertiesof these materials. During FY 1988,20 LANLgroups and 14 outside laboratories irradiatedmaterials at the OWR, for a total of 13 838samples. This value is typical of the annualnumber of OWR irradiations over the past8 yr. As a designated DOE User Facility, theOWR is available to non-DOE organizationssuch as universities. Harvard University,Brigham Young University, University ofNew Mexico, University of Alaska, and theUniversity of Washington have all made useof the reactor facilities in the past year.

Roughly two-thirds of the above samplesare submitted to OWR personnel for neutronactivation analysis (NAA), which is a highlysensitive and accurate method of assayingbulk materials nondestructively for trace levelsof a large number of elements. The main NAAmethod used at the OWR involves irradiationof the sample material with slow neutrons,followed by high-resolution detection of thegamma rays emitted from the sample byradioactive isotopes formed through captureof neutrons by the sample elements. Theindividual gamma rays can be uniquely



identified with specific elements, and theintensity of each gamma ray gives a directmeasure of the element abundance.Approximately 50 elements can be observedby this method (some at the part-per-billionlevel) by recording spectra at 20 min, 3 days,and 3 weeks after irradiation.

The automated NAA facilities at the OWRare reputed to be the best in the US. A widevariety of sample types was assayed in FY 1988,including human urine, soil, water, oils (for PCBcontent), biological samples, air filters, lunarand meteoric materials, geologic materials,organic foams, plastics, superconductors, and"pure" metals and chemicals such as beryllium,palladium, and boron carbide. During the year,we developed a successful method of assayingfor silicon in geologic and biologic materials;the method involves fast neutron irradiation ofthe samples in a newly installed, boron-shieldedepithermal-neutron facility, which makes silicondetectable through the 29Si(n,p)29Al reaction.

A formal proposal to replace the 32-yr-oldOWR with a new facility by the mid 1990s hasbeen submitted to senior management for theirconsideration. The suggested plan is to operatethe OWR until the new reactor is operationalso that experimenters will experience nointerruption in their local access to an intenseneutron flux. The proposal recommends that thenew reactor be designed and built by an externalcontractor as a turnkey facility, have a thermalpower of ~10 MW, and be inherently safe. Itsexperimental capabilities would be at least asextensive as those now available at the OWR.The replacement reactor would likely be sitednear Technical Area 48 rather than Los Alamoscanyon, partly because of lack of space in thecanyon and partly to place the reactor closer tothe major users.

Table 1. Experiments Performed at the OWR in FY 1988

Organization Experiment

Los Alamos National LaboratoryP-3P-8P-15ESS-11WX-3WX-5WX-5MST-3INC-5INC-5/P-DOINC-7M-1N-1

Battelle Northwest

(n,p) and (n,a) cross-section measurementsPosition-sensitive neutron detector testsFiltered beam resonance capture studiesNeutron radiographyNeutron radiographyRetention of 3He in tritidesNeutron diffraction studiesNeutron diffraction studiesDevelopment tests of new (n,y) facilityNeutron capture gamma-ray measurementsNeutron capture gamma-ray measurementsRadiation damage to explosivesSpent fuel element measurementsRadiation damage to CTR-type metals

TOTAL

fapmimtHour*

10215

2392

23506265

1944

71197

375126214



The ICON Facility

Lee F. Brown, John R. FitzPatrick,Thomas R. Mills, Charles A. Lehman,Michael G. Garcia, Troy A. Nothwang,Glenda E. Oakley, Robert £. Baran,Kathryn D. Elsberry, Shirley R. Roybal,Hong Bach, B. B. Mclnteer, andJoe G. Montoya

The function of the ICON facility located atTA-46 is to isolate large quantities of individualisotopes of certain light elements, such ascarbon, oxygen, and nitrogen (hence, thefacility name). The separations are carried outby cryogenic distillation in vertical distillationcolumns, some of which are more than 200 ftlong. The separated isotopes, or compoundscontaining these isotopes, are used in researchactivities at Los Alamos and at many otherinstitutions. For example, separated nitrogenisotopes are widely used as tracer materials infield studies of the nitrogen cycle in agriculturalresearch. The isotopic materials are sold at costto Los Alamos investigators or are available tothe general research community through EG&GMound.

During FY1988, the ICON program'sobjectives included production of stable isotopesof nitrogen, oxygen, and neon; improving theprocesses for separating these isotopes;developing new processes for separating stableisotopes; and providing chemical support to theseparation processes.

Stable Isotopes ProductionWe obtain nitrogen and oxygen isotopes bycryogenic distillation of nitric oxide and producea neon isotope by cryogenic distillation of neon.Table 7.2 shows our production for FY 1988.The column complex for distilling CO to obtain13CO and 12CO was on cold standby this yearbecause US requirements for stable carbonisotopes could be met from other sources.

The amounts of 15N and 18O produced wereless than our 9-kg/yr capacity for each. When ahole developed near the bottom of the principalfirst-stage nitric-oxide distillation column inearly July, we shut down the 200-ft first-stagecolumn for removal and repair.

The repaired first-stage column will berestarted early in FY 1989. For FY 1989,we have scheduled lower production ratesbecause of a decrease in demand. As soon asthe principal first-stage column is restarted,the three smaller first-stage columns will beshut down and put on standby.

Process ImprovementProduction of 17O this year barely metdemand, and need for 17O could increase incoming years. Consequently, we are developingplans to incorporate an unused column intothe NO distillation process to separate the1 kg/yr of 17O that is fed to the system butnot recovered. We will implement these planswhen need for additional 17O is apparent.

This year we made system changes toimprove the facility's safety and impact on theenvironment. An acid storage and containmentsystem was constructed for fresh acid feedingand storage of waste acids, vent systems wereimproved for better plant air quality, and aliquid-nitrogen vent system was changed sothat ground fog would not develop in the areaaround the building.

New Processes for Stable IsotopeSeparationPositron-emission tomography's use of18O water may exceed presen* internationalproduction capability in the mid-1990s.Therefore, we have developed plans toconvert our CO distillation complex to handleO2 distillation. When it is necessary, we willbe able to implement these plans and increasethe ICON Facility's 18O separation.

This year we built a new experimental stillto explore the possibility of separating stableisotopes of other light elements by distillation.The new column, 1.5 m long by 1.4-cm i.d.,is filled with wire helix packing (Heli-Pak) andis temperature controlled by thermal balancebetween a helium cryogenic refrigerator andcolumn heaters. Preflooding the columnimproves the separation factors markedly.We distilled CO, which has known separationfactors, to determine how many stages areneeded in the column. By measuring thei2CA3C separation, we concluded 75 plates areadequate for CO distillation.



We successfully used this column to separatesilicon, sulfur, and chlorine isotopes throughdistillation of SiF4, SF4, COS, HCi, and CI2.The observed separation factors in SiF4 and SF4

are sufficient to indicate that these compoundscan be employed to produce silicon and sulfurisotopes. From previous work, we know that H2Sis an alternative to SF4 for sulfur separation.The chlorine separation factor of 1.0010 to1.0012 we obtained with HC2 is large enoughto show that we can use HC7 distillation toenrich chlorine isotopes.

Chemistry SupportThe chemistry subsection of the ICON Facilityconducts chemistry research to support theprocessing and conversion of isotopicallyenriched nitric oxide.

Among other efforts, we have developed aprogram to reconcile results from direct massspectrometric analysis of NO with thoseobtained when NO is "sparked" or placed inan RF discharge and converted to N2 and O2."Sparking" is used where mercury is employedto reduce a nitrate salt or nitric acid to NO.In such situations, the oxygen is typically ofnatural isotopic abundance, and the nitrogenisotopic distribution is determined from them/z peaks of 28, 29, and 30.

We are developing a small-sample electrolysisapparatus that will convert labeled watersamples to oxygen. Using sodium bromide orpotassium bromide as a source of ions does notappear as successful as using a sodiumamalgam. Our goal is to find a reliable methodto back up the CO2 exchange method wecurrently use for oxygen isotopic analysis. Table 7.2. Stable Isotope Production by the

ICON FaciUty During FY 1988

Isotope

1 5 N

1 5 N

1 5 N16O170170ISOISO

QuantityProduced

(«*>

2.121.082.82

205.80.0830.2573.103.882.78

EnrichaMttt(%)

10+60-85

96+99.96+

20-3536-50

10+95+90+

Isotope and Nuclear Chemistry Division Anhual Report FY 1988 77

Appendix: Personnel

List of Division Personnel by Group

INC-DO (667-4457)Buildings RC-29 and 34, TA-48

* Donald W. BarrDivision Leader

* Alexander J. Gancarz, Jr.Deputy Division Leader

* Bruce R. ErdalTechnical Coordinator

* Eugene J. PetersonTechnical Coordinator

* Basil I. SwansonTechnical Coordinator

Barbara J. AndersonJoann W. BrownAudrey L. GigerJaney HeadstreamJody H. HeikenS. Kathleen Kelly

INC-4 (667-6045)Buildings 3 and 150, TA-21;Building 88, TA-46

* Robert R. RyanGroup Leader

* Phillip G. EllerDeputy Group Leader

* Stephen F. Agnewf Robert E. Baran* James R. Brainard* Lee F. Brown

Section Leader* Stephen D. Conrad son

Douglas G. EckhartDeborah S. EhlerScott A. Ekberg

* Phillip G. EllerSection Leader

Kathryn D. Elsberry* James A. Fee

Section LeaderMarielle Fenstermacher

* John R. FitzPatrick

Staff Member.No longer working in INC Division.

Michael G. GarciaJohn L. HannersJudith C. HutsonGordon D. JarveninScott KinkeadRichard J. KissaneGregory J. Kubas

Laboratory FellowJiri KubicekJudith A. LandaicheCharles A. Lehman, Jr.Michael W. MatherRaymond C. MedinaThomas R. MillsCleo M. NaranjoTroy A. NothwangGlenda E. OakleyValerie D. OrtizJohn D. PursonShirley R. RoybalKenneth V. SalazarAlfred P. Sattelberger

Section LeaderPenelope A. SpringerClifford J. UnkeferPat J. UnkeferWilliam E. WagemanWilliam H. WoodruffTatsuro Yoshida

INC-5 (667-4151)Omega Site, TA-2

* Merle E. BunkerGroup Leader

* Michael M. MinorDeputy Group Leader

f Glen E. Barber* Michael M. Denton* Sammy R. Garcia

Michael D. KaufmanJanet S. Newlin

* Gerald F. RamseyThomas C. RobinsonCathy Schuch

* Terry W. SmithSection Leader

* John W. Starner

SO Isotope and Nuclear Chemistry Division Annual Report FY 1988

Appendix: Person nel

INC-7 (667-4498)Radiochemistry Building, TA-48

* David B. CurtisGroup Leader

* Robert W. CharlesDeputy Group Leader

Ruben D. Aguilar*~ Mohammed Alei

Phyllis L. BacaHong T. BachJoseph C. BanarGregory K. Bayhurst

* Timothy M. Benjamin* Ernest A. Bryant* John H. Cappis* Clarence J. Duffy~ Suzanne Dye* Bryan L. Fearey* David L Finnegan*t Jeffrey S. Gaffney* David R. Janecky* AllenS. Mason* Arend Meijer* Charles M. Miller

Project Leaderf Lia M. Mitchell* Eugene J. Mroz* Michael T. Murrell* A. Edward Norris* Allen E. Ogard* Jose A. Olivares* Richard E. Perrin* Jane Poths

Eddie L Rios* Pamela Z. Rogers* Donald J. Rokop

Technical CoordinatorC. Elaine Roybal

* Norman C. SchroederHenrietta Tixier

* Kurt WolfsbergSection Leader

INC-U (667-4546)Radiochemistry Building, TA-48;LAMPF Building, TA-53

* William R. DanielsGroup Leader

* Genevieve F. GrishamDeputy Group Leader

* David C. Moody, IIIDeputy Group Leader

* Moses AttrepM. Romayne BettsRoland A. Bibeau

* Scott M. Bowen* Gilbert W. Butler

Section Leader* Edwin P. Chamberlin

Section LeaderMichael R. Cisneros

* David D. Clinton* Dean A. Cole

Joe CortezSamia DavisJoy Drake

* Deward W. EfurdSection Leader

Maureen A. Flynn* Malcolm M. Fowler* Russell E. Gritzo* Sara B. Helmick

Allen N. Herring II* David E. Hobart

Gregory M. Kelley* Sylvia D. Knight

Marcella L. KramerMarjorie E. Lark

* Francine 0 Lawrence* Lon-Chang Liu

Calvin C. LongmireRobert M. LopezCarla E. LowePatrick S. Lysaght

* Michael R, MaclnnesSixto Maestas

i! Janet Mercer-Smith* Geoffrey G. Miller

Alan J. Mitchell* David E. Morris

Thomas A. Myers* Charles J. Orth

Laboratory FellowMartin A. Ott

Isotope and Nuclear Chemistry Division Annual Report FY19SS 81

Appendix: Personnel

Charles P. PadillaPhillip D. PalmerDennis R. PhillipsFrederick R. RoenschRobert S. RundbergLisa M. SchneiderRaymond G. SchofieldFranklin H. SeurerRichard C. StaroskiFrederick J. SteinkrugerZita V. SvitraWayne A. TaylorKimberly W. Thomas

Section LeaderJoseph L. ThompsonInez R. TriayLarry S. UlibarriFrank O. ValdezDavid J. Vieira

Section LeaderJerry B. Wilhelmy

Laboratory FellowJan M. WoutersMary Anne Yates

Laboratory Associates

Ruth Capron, INC-4* Bruce J. Dropesky, INC-DO

Frank Newcom, INC-5Raymond Vandervoort, INC-4

* Herbert Williams, INC-5David Yarnell, INC-11

Postdoctoral Appointees

Kent D. Abney, INC-4Thomas Blaich, INC-11Timothy P. Burns, INC-11Rajeev Chemburkar, INC-4Robert J. Donohoe, INC-4Olof Einarsdottir, INC-4Eduardo Garcia, INC-4Steven J. Goldstein, INC-7David Houck, INC-4

f Patrick M. Killough, INC-4Juan Lopez-Garriga, INC-4

f NancyA. Marley, INC-71 Kimberly A. Martin, INC-4

Eric Neiderhoffer, INC-4Jon B. Nielsen, INC-4David Pinnick, INC-4Nancy Sauer, INC-4Louis D. Schulte, INC-11Paul H. Smith, INC-4Carleton D. Tait, INC-4William VanderSluys, INC-4Jeffrey B. Weinrach, INC-4

JRO Fellows

Carol Burns, INC-4David L. Clark, INC-4

t Jeanette C. Roberts, INC-11

Summer Teacher

Leonard R. Quintana, INC-11

Graduate Research Assistants

Marieluise Begemann-Blaich, INC-11Katherine Bradley, INC-4Peter Dorhout, INC-4

t Marci D. Ferrell, INC-4Janet Griego, INC-4Monica Hilliard, INC-4John A. Keightley, INC-4Dawn Lewis, INC-11Theresa A. Miller, INC-7Cheryl L. Peach, INC-7Julia A. Peck, INC-4Eric W. Prestbo, INC-7William B. Sanborn, INC-4Hardy Siefert, INC-11Bradley E. Sturgeon, INC-4

i Daniel VanGent, INC-5Lori VanderSluys, INC-4John Wilson, INC-11Jonathan J. Zieman, INC-7

Undergraduate Assistants

William J. Caperton, INC-11Jason N. Ceballes, INC-4Lynda S. Halloran, INC-DOMichael Y. Han, INC-4Lillian Hinsley, INC-DOLily Hsu, INC-4Kermit Lopez, INC-11Sherri Newmyer, INC-11David A. Nix, INC-11Joanna K. Norman, INC-11Debra E. Smith, INC-4

Undergraduate Interns

I Allyn Bates, INC-7~ Jonathan Briggs, INC-4

Octavio Ramos, Jr., INC-11/DOJean Y. Yang, INC-11

Co-op Students

William H. Straight, INC-7 (DIR)John R. VanMarter, INC-11

82 Isotope and Nuclear Chemistry Division Report 1988

Appendix: Advisory Committee

Isotope and Nuclear Chemistry Division Advisory Committee

Committee Chairman

(1985-1989) Harry B. GrayChemistry 127-72California Institute of TechnologyPasadena, CA 91125

Committee Members

(1988-90) Gordon E. Brown, Jr.Department of GeologyStanford UniversityStanford, CA 94305

(1989-91) Gary M. HieftjeDepartment of ChemistryA169 Chemistry BuildingIndiana UniversityBloomington, IN 47401

(1986-89) Heinrich D. HollandDepartment of Geological SciencesHoffman LaboratoryHarvard UniversityCambridge, MA 02138

(1987-89) Anthony TurkevichEnrico Fermi InstituteThe University of Chicago5630 Ellis AvenueChicago, IL 60637

(1988-90) Henry N. WagnerDivision of Radiation Health Scienceand Nuclear Medicine

Johns Hopkins University615 N. Wolfe StreetBaltimore, MD 21205

(1984-89) George E. WalkerDepartment of PhysicsSwain West 233Indiana UniversityBloomington, IN 47405

Isotope and Nuclear Chemistry Division Atinual Report FYI9SS 83

Appendix: Program Funding

Funding Sources

FY 1988 Funding Profile

Operating $26.8 MCapital $ 1.7 M

Total $28.5 M

Defense Programs

Laboratory R&D

Work for Others

DOE 9%NIH 4%DOD 2%OTHER 1%

Energy Research

OBES 6%OHER 6%OHENP 4%

Nuclear Energy


Appi'ndix: Program Funding

Project Title Principal Investigator $K

Weapons Chemistry(DOE/OMA)(DoD.)Isotope Separator ConstructionOther

Biochemistry and Nuclear MedicineMedical Radioisotopes Research (DOE/OHERjNational Stable Isotopes Research (NIHjImaging Agents for Lymph Nodes i DOE/OHER)Radiopharmaceuticals (ISR)Mechanisms of Respiration (NIH,)C 1 3 NMR and Metabolism (DOE/OHER)Bacterial Toxins (ISRJMethylotrophic Bacteria Metabolism (DOE/OBES)Signal Peptides (ISR)Red Blood Cell Modeling (ISRjSuperoxide Dismutase (NIH)Vibrational Spectroscopy (NIH)Biomedical Research Support (NIH)

Environmental and GeochemistryYucca Mountain Project (DOE/NV)Geochemistry Research (DOE/OBES)Radionuclide Migration Project (DOE/NV)Data Base Review (DNAjAtmospheric Chemistry of Organic Oxidants

(DOE/OHER)Continental Scientific Drilling Project (ISR)Natural Plutonium Geochemistry (DOE/ANL)Biotechnology (ISR)Iridium Anomaly (ISR)Geochemistry: Advanced Concepts (DOE/OBES)Instrumentation (ISR)Advanced Mass Spectrometry (IGPP)Iridium Mini-Grant (IGPP)INAA Analysis fEPRIjAlligator Rivers Analogue (ANST)Nuclear Microprobe Mini-Grant (IGPP)White Garnets on Navajo Nation (LANL)Elemental Abundances (NASA)

Actinide and Transition Metal ChemistryTransition Metal Mediated Reactions (DOE/OBES)Stereoselective Ligands HSR)Actinide Organometallic Chemistry i DOE/OBES JActinide Chemistry (ISR)Actinides in Near-Neutral Solution 'DOE/OBES)Structure-Function Relationships 'ISRjHydrogen UptakePhotodynamics CISR)

D.W. BarrD.W. BarrE.P. ChamberlinD.W. Barr

D.C. MoodyJ.A. FeeJ.A. Mercer-SmithJ.A. Mercer-SmithJ.A. FeeJ.A. FeeP.J. UnkeferC.J. UnkeferJ.R. BrainardJ.A. FeeJ.A. FeeW.H. Woodruff

E.S. PateraR.W. CharlesJ.L. ThompsonA.S. MasonJ.S. Gaffney

R.W. CharlesD.B. CurtisP.J. UnkeferC.J. OrthR.W. CharlesJ.S. GaffneyM.M. FowlerC.J. OrthE.J. MrozD.B. CurtisD.R. JaneckyR.W. CharlesC.J. Orth

G.J. KubasG.D. JarvinenA. P. SattelbergerA.R SattelbergerD.E. HobartR.R. RvanG.J. KubasW.H. Woodruff

1117841140

161013239

900544300276218209187115103103

968421

3156

2786740336263147

98957550503535271712

865

4785

356310225197148128118

1580

Isotope and Xuclear Chemistry Division Annual RrpoH FY lfiSS .So

Appendix: Program Funding

Project Title Principal Investigator SK

Materials ChemistrySynchrotron Radiation/Neutron Scattering (ISR)Chemistry of Shocked Energetic Materials (ISR)Materials Under Extreme Conditions (ISR)Chemical Modification and Structure (ISR)Mixed Valence Solids (ISR)Optical Spectroscopy (ISR)Carbon Disulfide/Molecule Studies (ONR)Chemistry of Reacting HEs (DoD)Structural Studies (ISR)Fuel Cells (Conserv. Renew. Energy)Synchrotron Radiation Research (ISR)High Reflectance Mirrors (DOE/OBES)CMS Research (ISR)

Nuclear Structure and ReactionsNuclear Chemistry Research—LAMPF (DOE/OHENP)Solar Neutrino Flux (DOE/OHENP)Double Beta Decay (ISR)Fission and Reaction Studies (DOE/OHENP)

Major FacilitiesICONS Production (MOUND)Omega West Reactor (LANDICON Facility (DOE/OHER)Other OWR ServicesUser Facility Agreement (WTC)Contaminated Solid Waste Burial (DOE)Ne2 2 Sales (LLNL)Neutron Irradiations (DOE)Irradiation of Minerals (NTT)

S.D. ConradsonB.I. SwansonB.I. SwansonR.R. RyanB.I. SwansonB.I. SvvansonB.I. SwansonS.F. AgnewR.R. RyanS.D. ConradsonS.D. ConradsonS.D. ConradsonB.I. Swanson

D.J. VieiraK. WolfsbergR.S. RundbergJ.B. Wilhelmy

L.F. BrownM.E. BunkerL.F. BrownM.E. BunkerM.E. BunkerM.E. BunkerL.F. BrownM.E. BunkerM.E. Bunker

Division Total

235190158100

999861585020201513

1117

630229167139

1165

1086352125444020201310

1710

26752


Appendix: Puh!iif)tionn

Publications

INC-4

S. F. Agnew, and B. I. Swanson, "Model for theDensity Dependence of Electronic AbsorptionBands: Application to Carbon Disulfide andother Molecules," in Shock Waves in CondensedMatter 1987, S. C. Schmidt and N. C. Holmes,Eds. (Elsevier, 1988), pp. 485-488.

S. F. Agnew, R. S. Mischke, and B. I. Swanson,"Pressure- and Temperature-Induced Chemistryof Carbon Disulfide," J. Phys. Chem. 92 (14),4201-4204 (1988).

L. R. Avens, and P. G. Eller, "Low-TemperatureFluorination of Actinides," Trans. Am. Nucl.Soc. 55, 246-247 (1987).

L. R. Avens, P. G. Eller, L. B. Asprey,K. D. Abney, and S. A. Kinkead, "AnalyticalApplications of Superacid Dissolution ofActinide and Lanthanide Substrates," J.Radioanal. Nucl. Chem. 123(2), 707-712 (1988).

N. R. Bastian, G. Diekert, E. C. Niederhoffer,B-K Teo, C. T. Walsh, and W. H. Orme-Johnson,"Nickel and Iron EXAFS of Carbon MonoxideDehydrogenase from Clostridiumthermoaceticum Strain DSM," J. Am. Chem.Soc. 110(16), 5581-5582 (1988).

D. B. Bush, and P. J. Langston-Unkefer,"Tabtoxinine-b-lactam Transport into CulturedCorn Cells: Uptake Via an Amino AcidTransport System," Plant Physiol. 85, 845-849(1987).

L. G. Butler, M. H. Zietlow, C-M Che,W. P. Schaefer, S. Sridhar, P. J. Grunthaner,B. I. Swanson, R. J. H. Clark, and H. B. Gray,"Translational Symmetries in the Linear-ChainSemiconductors K4[Pt2(P2O5H2)4X]*reH2O(X=C1, Br, I;," J.Am. Chem. Soc. 110'4), 1155-1162 (1988).

A. Campion and W. H. Woodruff, "MultichannelRaman Spectroscopy,' Anal. Chem. 59(2),1299A-1308A(1987).

G. S. Conary, A. A. Russell, R. T. Paine,J. H. Hall, and R. R. Ryan, "Synthesis andCoordination Chemistry of 2-(Diisopro-

poxyphosphinojpyridine AT,P-Dioxide. Crystaland Molecular Structure of Bi.s[2-(diisoprop<jxy-phosphinojpyridine Ar,P-Dioxide]-lanthanumNitrate," Inorg. Chem. 27(18), 3242-3245 a988).

S. D. Conradson, A. P. Sattelberger, andW. H. Woodruff, ' X-Ray Absorption Study ofOctafluorodirhenatedll): EXAFS Structures andResonance Raman Spectroscopy ofOctahalodirhenates, -/. Am. Chem. Soc. 110(4),1309-1311 (1988;.

S. D. Conradson, M. A, Stroud, M. H. Zietlow,B. I. Swanson, D. Baeriswyl, and A. R. Bishop,"Charge Density Waves and Local States inQuasi-One-Dimensional Mixed ValenceInorganic Complexes," IAEA IC/87/315(Miramare-Trieste, 1987), and Solid StateCommun. 65(7), 1405-1409 (1988).

S. D. Conradson, M. A. Stroud, M. H. Zietlow,B. I. Swanson, D. Baeriswyl, and A. R. Bishop,"Charge Density Waves and Local States inQuasi-One-Dimensional Mixed ValenceInorganic Complexes," IAEA IC/87/315(Miramare-Trieste, 1987), and Solid StateCommun. 65(7), 1405-1409 (1988).

S. D. Cope, D. K. Russell, H. A. Fry, L. H. Jones,and J. E. Barefield, "Analysis of the n :

Fundamental Mode of HTO," -J. Mol. Spectrosc.127, 464-471 (1988).

D. T. Cromer, H. L. Ammon, and J. R. Holden,"A Procedure for Estimating the CrystalDensities of Organic Explosives," Los AlamosNational Laboratory report LA-11142-MS^November 1987).

D. T. Cromer, J. H. Hall, K-Y. Lee, and R. R.Ryan, "The Structure of the Ethylene-diammonium Salt of 3-Nitro-l,2,4-triazol-5-one,C9H4( NH3)2-2C2N4O3H, Ada Cryst C 44,1144-1147 (1988").

D.T. Cromer, K-Y Lee, and R. R. Ryan,Structures of Two Polymorphs of 1,1 -Dinitro-

3,3-azo-l,2,4-triazole,' Acta Cryst. C44'9.u1673-1674 (1988).

D. T. Cromer, R. R. Ryan, and M. D. Coburn.The Structure of 3,5-Dinitroisoxazole, Acta

Crvst. C43<10.;, 2011-2013 '1987'.

Isotope and Xuclear Chemistry Division Annual Rvpnrt b~Y

Appendix: Pu blications

W. L. Earl, R. L. Wershaw, and K. A. Thorn,"The Use of Variable Temperature and Magic-Angle Sample Spinning in Studies of FulvicAcids," J. Magn. Reson. 74, 264-274 (1987).

J. Eckert, G. J. Kubas, and A. J. Dianoux,"Rotational Tunneling of Bound H2 in aTungsten Complex," J. Chem. Phys. 88(1),466-468 (1988).

D. D. Ensor, G. D. Jarvinen, and B. F. Smith,"The Use of Soft Donor Ligands, 4-Benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thioneand 4,7-Diphenyl-l,10-phenanthroline, forImproved Separation of Trivalent Americiumand Europium," Solvent Extraction and IonExchange 6(3), 439-445 (1988).

J. A. Fee, B. H. Zimmerman, C. I. Nitsche,F. Rusnak, and E. Miinck, "The Cytochromecaa% from Thermus thermophilus," ChemicaScipta 28A, 75-78 (1988).

E. Garcia, N. N. Sauer, R. R. Ryan, A. Williams,and P. G. Eller, "Neutron Powder DiffractionStudy of the Products from FluorinatingYBa2Cu3O7_,j at Room Temperature and at400°e," J. Mat. Res. 3(5), 819-824 (1988).

E. Garcia, R. R. Ryan, N. N. Sauer, Z. Fisk,B. Pierce, M. Fluss, and L. Bernadez,"Synthesis and Superconducting CriticalTemperature of YBa2Cu3

1807-d,'1 Phys. Rev. B38(4), 2900-2902 (1988).

L. Hedberg, K. Hedberg, P. G. Eller, andR. R. Ryan, "Dioxygen Difluoride: ElectronDiffraction Investigation of the MolecularStructure in the Gas," Inorg. Chem. 27(2),232-235 (1988).

D. E. Hoekenga, J. R. Brainard, andJ. Y. Hutson, "Rates of Giycolysis andGlycogenolysis During Ischemia in Glucose,Insulin and Potassium (GIK) Treated GuineaPig Hearts: A 13C,31P Nuclear MagneticResonance Study," Circulation Res. 62(6),1065-1074(1988).

D. R. Houck, J. L. Hanners, and C. J. Unkefer,"Biosynthesis of Pyrroloquinoline Quinone. I.Identification of Biosynthetic Precursors Using13C Labeling and NMR Spectroscopy," J. Am.Chem. Soc. 110(20), 6920-6921 (1988).

P. J. Jackson, C. J. Unkefer, K. Watt,J. A. Doolen, and N. J. Robinson, "Poly—ig-glutamylcysteine) Glycine: A FunctionalAnalogue of Metallothionein in Angiosperms,"Proc. Nat. Acad. Sci., USA 84,6619-6623 (1987).

L. H. Jones, and S. A. Ekberg, "HinderedRotation and Site Structure of CD4 Trapped inRare Gas Solids," J. Chem. Phys. 87(8),4368-4370(1987).

B. S. Jorgensen, M. Aldissi, R. Liepins, andS. F. Agnew, "Highly Oriented UnsubstitutedPolydiacetylene," Proc. Symposium onNonlinear Optical Properties of Polymers, 1987(Materials Research Society, 1988), pp. 379-384.

T. J. Knight and P. J. Langston-Unkefer,"Adenine Nucleotides as Allosteric Effectors ofPea Seed Glutamine Synthetase," J. BiologicalChem. 263(23), 11084-11089 (1988).

T. J. Knight and P. J. Langston-Unkefer,"Enhancement of Symbiotic Dinitrogen Fixationby a Toxin-Releasing Plant Pathogen," Science241,951-954(1988).

G. J. Kubas, "Molecular Hydrogen Complexes ofthe Transition Metals," Accts. Chem. Res. 21(3),120-128 (1988).

G. J. Kubas, "Molecular Hydrogen Coordinationto Transition Metals," Comments Inorg. Chem.7(1X17-40(1988). Invited.

G. J. Kubas, R. R. Ryan, and C. J. Unkefer,"Molecular Hydrogen Complexes. 5.Electronic Control of h2-H2 vs. DihydrideCoordination. Dihydride Structure ofMoH2(COXR2PC2H4PR2)2 for R=Et, i-Bu vs. h2-H2 for R=Ph," J. Am. Chem. Soc. 109(26), 8113-8115 (1987).

K. A. Kubat-Martin, G. J. Kubas, andR. R. Ryan, "Reaction of Sulfur Dioxide with (h5-C5Me5)Ru(CO)2H: Insertion of SO2 into the Ru-H Bond and Oxygen Transfer to Form (h5-C5Me5)Ru(CO)2SO3H," Organometallics 7(7),1657-1659 (1988).

E. M. Larson, P. G. Eller, J. D. Purson,C. F. Pace, M. P. Eastman, R. B. Greegor, andF. W. Lytle, "Synthesis and StructuralCharacterization of CaTiO3 Doped with


Appendix: Publications

0.05-7.5 Mole% Gadolinium(III)," J. Solid StateChem. 73, 480-487 (1988).

M. W. Mather, "Base Compostion-IndependentHybridization in Dried Agarose Gels: Screeningand Recovery for Cloning of Genomic DNAFragments," BioTechniques 6(5), 444-447 (1988).

B. H. Meier, and W. L. Earl, "A Double-QuantumFilter for Rotating Solids," J. Am. Chem. Soc.109(26), 7937-7942 (1987).

H. L. Nekimken, B. F. Smith, G. D. Jarvinen,E. J. Peterson, and M. M. Jones, "Computer-Controlled Flow Injection Analysis System forOn-Line Determination of Distribution Ratios,"Analytical Chem. 60(14), 1390-1393 (1988).

D. W. Reagor, A. Migliori, Z. Fisk, R. D. Taylor,K A. Martin, and R. R. Ryan, "MicrowaveCollective Transport in Single-crystalEu2Cu04 ," Phys. Rev. B 38(7), 5106-5109(1988).

B. A. Robinson, J.W. Tester, and L.F. Brown,"Reservoir Sizing Using Inert and ChemicallyReacting Tracers," SPE Formation Evaluation,227-234 (March, 1988).

F. M. Rusnak, E. Munck, C. I. Nitsche,B. H. Zimmermann, and J. A. Fee, "Evidence forStructural Heterogeneities and a Study ofExchange Coupling: Mossbauer Studies ofCytochrome 0^83 from Thermus thermophilus,"J. Biological Chem. 263(34), 16328-16332U987).

J. M. Saber, KB. Kester, J.L. Falconer, andL.F. Brown, "A Mechanism for the Sodium OxideCatalyzed CO2 Gasification of Carbon,J. Catalysis, 109, 329-346 (1988).

N. N Sauer, E. Garcia, J. A. Martin, R. R. Ryan,P. G. Eller, J. R. Tesmer, and C. J. Maggiore,"Fluorination of the High Tc SuperconductorsYBa2Cu307.d and GdBa2Cu3O7.d," J. Mat. Res.3(5), 813-818(1988).

J. R. Schoonover, R. B. Dyer, W. H. Woodruff,G. M.Baker, M. Noguchi, and G. Palmer,"A Comparison of the Resonance RamanProperties of the Fast and Slow Forms ofCytochrome Oxidase," Biochem. 27, 5433 (1988).

B. F. Smith, D. Jarvinen, G. G. Miller,R. R. Ryan, and E. J. Peterson, "SynergisticExtraction Studies of Am(III) and Eu(III) fromPerchloric Acid with 4-Benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione(BMMPT)and Tri-n-octylphosphine Oxide (TOPO) inBenzene," Solvent Extraction and Ion Exchange5(5), 895-908 (1987).

B. I. Swanson, M. A. Stroud, S. D. Conradson,and M. H. Zietlow, "Observation of a PressureInduced Reverse Peierls Instability in theQuasi-One-Dimensional Mixed Valence SolidK4[Pt2(P2O5H2)4Br]-3H2O," Solid StateCommun. 65(11), 1405-1409 (1988).

B. I. Swanson, S. F. Agnew, and N. R. Greiner,"Static High Pressure Study of Nitric OxideChemistry: Proposed Mechanism for NitricOxide Detonation," in Proc. Eighth Symposium(International) on Detonation, Albuquerque,New Mexico, July 15-19,1985 (April 1988),pp. 715-724.

W. G. Van Der Sluys, C. J. Burns, J. C. Huffman,and A. P. Sattelberger, "Uranium AlkoxideChemistry. 1. Synthesis and the Novel DimericStructure of the First Homoleptic Uranium(III)Aryloxide Complex," J. Am. Chem. Soc. 110(17),5924-5925 (1988).

T. E. Walker, C. J. Unkefer, and D. S. Ehler,"The Synthesis of Carbon-13 EnrichedMonosaccharides Derived from Glucose andMannose," J. Carbokydr. Chem. 7(1), 115-132(1988).

K. H. Whitmire, J. M. Cassidy, A. L. Rheingold,and R. R. Ryan, "A Series of Thallium-IronCarbonyl Cluster Molecules: StructuralComparisons of [Et4N]2 {Tl2Fe4(CO)16 j ,[Et4]4[Ti4Fe8(CO)30] and[Et4N]6[Tl6Fe10(CO)36]," Inorg. Chem. 27(8),1347-1353(1988).

W. H. Woodruff, R. B. Dyer, andJ. R. Schoonover, "Resonance RamanSpectroscopy of Blue Copper Proteins," inBiological Applications of Raman Spectroscopy,Vol. 3, Resonance Raman Spectra of Heine andMetalloproteins, T. G. Spiro, Ed. (Wiley-Interscience, New York, 1988),Chap. 9,pp. 413-438.



C. S. Yoo, J. J. Furrer, G. E. Duvall, S. F. Agnew,and B. I. Swanson, "Effects of Dilution on theUltraviolet and Visible Absorptivity of CS2under Static and Shock Compression," J. Phys.Chem. 91(27), 6577-6578 (1987).

Patents

L.B. Asprey and P. G. Eller, "Method forRecovery of Actinides from Refractory Oxidesthereof Using O2F2," U.S. Patent #4,724,127,issued February 9,1988.

J.R. FitzPatrick, J. G. Dunn, and L. R. Avens,"Method for Removal of Plutonium Impurityfrom Americium Oxides and Fluorides," U.S.Patent #4,710,222, issued December 1,1987.

E. Fukushima, A. R. Rath, and S.B.W. Roeder,"Apparatus for Unilateral Generation of aHomogeneous Magnetic Field," U.S. Patent#4,721,914, issued January 26,1988.

INC-5

W. L. Talbert, Jr., M. E. Bunker, and J. W.Starner, "Optimization of a He-Jet ActivityTransport System to Use at LAMPF," Nucl.Instr. Methods B26, 345 (1987).

W. L. Talbert, Jr., J. W. Starner, R. J. Estep,S. J. Balestrini, M. Attrep, Jr., D. W. Efurd,and F. R. Roensch, Phys. Rev. C 36,1896 (1987).

R. G. Helmer, C. W. Reich, M. E. Bunker, andJ. W. Stamer, "Decay of 150Tb," Idaho NationalEngineering Laboratory report EGG-PHY-7569(October 1987).

D. E. Robertson, M. P. Bergeron, D. A. Myers,K. H. Abel, C. W. Thomas, D. R. Champ,R. W. Killey, G. L. Moltyaner, and J. L. Young,"Demonstration of Performance Modeling of aLow-Level Waste Shallow-Land Burial Site,"Pacific Northwest Laboratory report PNL-6175,Vol. 1, NUREG/CR-4879 (November 1987).

P. E. Koehler, C. D. Bowman, F. J. Steinkruger,D. C. Moody, G. M. Hale, J. W. Starner, S. A.Wender, R. C. Haight, P. W. Lisowski, and W. L.Talbert, "7Be(n,p)7Li total cross section from 25meV to 13.5 keV," Phys. Rev. C 37, 917 (1988).

D. A. Wrobleski, K. H. Abel, A. J. Gray, andJ. M. Williams, "Potential Foams and MetalFoils for Cosmic Dust Capture," Los AlamosNational Laboratory report LA-11271-MS(July 1988).

J. Stix, F. E. Goff, M. P. Gorton, G. Heiken, andS. R. Garcia, "Restoration of CompositionalZonation in the Bandelier Silicic MagmaChamber Between Two Caldera-FormingEruptions: Geochemistry and Origin of theCerro Toledo Rhyolite, Jemez Mountains, NewMexico," J. Geophys. Res. B6,6129 (1988).

INC-7

S. F. Agnew, T. Miller, S. Eckberg, andB. I. Swanson, "Analysis of Diamond-AnvilCell Reaction Products: High-PressureDecomposition of Nitromethane," in "Isotopeand Nuclear Chemistry Division Annual ReportFY 1987, October 1986-September 1987," LosAlamos National Laboratory reportLA-11291-PR (May 1988), pp. 42-46.

K H. Birdsell, P. G. Stringer, L. F. Brown,G. A. Cederberg, B. J. Travis, and A. E. Norris,"Modeling the Exploratory Shaft Diffusion Test,"Los Alamos National Laboratory documentLA-UR-87-307 (January 1S88).

R. W. Charles, "State of GeochemicalEquilibrium in California State Well 2-14:The Salton Sea Scientific Drilling Project,"in "Isotope and Nuclear Chemistry DivisionAnnual Report FY 1987, October 1986-September 1987,' Los Alamos NationalLaboratory report LA-11291-PR (May 1988),pp. 116-120.

R. W. Charles, C. Navarro, D. R. Janecky, andC. Wells, "Advanced Downhole SamplerPrototype," in Proceedings of the WellboreSampling Workshop, November 1987, SandiaNational Laboratories report SAND87-1918(1987), pp. 72-73.

B. M. Crowe, D. L. Finnegan, W. H. Zoller, andW. V. Boynton, "Trace Element Geochemistry ofVolcanic Gases and Particles from 1983-1984Eruptive Episodes of Kilauea Volcano,"J. Geophys. Res. 92 (B13), 13,708-13,714(December 1987).



C. J. Duffy, "Control of Low- TemperatureMineral Alteration by Aqueous Silica Activity,"in "Isotope and Nuclear Chemistry DivisionAnnual Report FY1987, October 1986-September 1987," Los Alamos NationalLaboratory report LA-11291-PR (May 1988),pp. 114-116.

B. L. Fearey, C. M. Miller, M. W. Rowe,J. E. Anderson, and N. S. Nogar, "Pulsed LaserResonance Ionization Mass Spectrometry(RIMS) for Elementally Selective Detection ofLead and Bismuth Mixtures," Anal. Chem. 60,1786-1791 (1988).

B. L. Fearey, D. C. Parent, R. A. Keller, andC. M. Miller, "Progress Toward the AnalyticalViability of Resonance Ionization MassSpectrometry," in "Isotope and NuclearChemistry Division Annual Report FY 1987,October 1986-September 1987," Los AlamosNational Laboratory report LA-11291-PR(May 1988), pp. 210-213.

B. L. Fearey, M. W. Rowe, J. E. Anderson,C. M. Miller, and N. S. Nogar, "ElementallySelective Detection of Lead and BismuthMixtures by Pulsed Laser Resonance IonizationMass Spectrometry," in "Isotope and NuclearChemistry Division Annual Report FY 1987,October 1986-September 1987," Los AlamosNational Laboratory report LA-11291-PR(May 1988), pp. 214-218.

D. L. Finnegan and E. A. Bryant, "Methods forObtaining Sorption Data from Uranium-SeriesDisequilibria," Los Alamos National Laboratoryreport LA-11162-MS (December 1987).

J. S. Gaffney, N. A. Marley, and I. R. Triay,"Looking Past Nuclear Winter," in "Isotopeand Nuclear Chemistry Division Annual ReportFY 1987, October 1986-September 1987," LosAlamos National Laboratory report LA-11291-PR (May 1988), pp. 232-233.

J. S. Gaffney, E. W. Prestbo, J. Zieman,W. H. Zoller, E. Franzblau, and C. J. Popp,"Monoterpene Moderation of Surface OzoneConcentrations in the Troposphere," in "Isotopeand Nuclear Chemistry Division Annual ReportFY 1987, October 1986-September 1987,"Los Alamos National Laboratory report LA-11291-PR (May 1988), pp. 233-235.

F. A. Gifford, S. Barr, R. C. Malone, andE. J. Mroz, "Tropospheric Relative Diffusionto Hemispheric Scales," Atmos. Environ. 22 (9;,1871 (1988).

S. J. Goldstein and S. B. Jacobsen, "Rare EarthElements in River Waters," Earth Planet. Sci.Lett. 88, 35-47 (1988).

S. J. Goldstein and S. B. Jacobsen, "Nd and SrIsotopic Systematics of River Water SuspendedMaterial: Implications for Crustal Evolution,"Earth Planet. Sci. Lett. 87, 249-265 (1988).

S. J. Goldstein and S. B. Jacobsen, "REE in theGreat Whale River Estuary, Northwest Quebec,"Earth Planet. Sci. Lett 88, 241-252 (1988).

D. R. Janecky, R. W. Charles, F. E. Goff, andJ. Hulen, "Geochemistry of Molybdenum-Bearing Assemblages in CSDP Well VC-2a,Valles Caldera, New Mexico," Trans. Am.Geophys. Union 68 (44), 469 (1987).

D. R. Janecky, R. M. Haymon, andT. M. Benjamin, "Trace-Element AnalysisApplied to Seafloor Hydrothermal Systemsand Processes: Using the Los Alamos NuclearMicroprobe," in "Isotope and Nuclear ChemistryDivision Annual Report FY 1987, October 1986-September 1987," Los Alamos NationalLaboratory report LA-11291-PR (May 1988),pp. 106-109.

D. R. Janecky and W. E. Seyfried, Jr.,"Transition Metal Mobility in Oceanic RidgeCrest Hydrothermal Systems at 350oC-425"C,'in Chemical Transport in MetasomaticProcesses, H. C. Helgeson, ed. (D. ReidelPublishing Company, 1987), pp. 657-688.

N. Kaffrell, P. Hill, J. Rogowski, H. Tetzlaff,N. Trautmann, E. Jacobs, P. De Gelder,D. De Frenne, K. Heyde, G. Skarnemark,J. Alstad, N. Blasi, M. N. Harakeh,W. A. Sterrenburg, and K. Wolfsberg,"Levels in 109Rh,' Nucl. Phys. A470,141-160(1987).

R. D. Loss, J. R. De Laeter, K. J. R. Rosman,T. M. Benjamin, D. B. Curtis, A. J. Gancarz,J. E. Delmore, and W. J. Maeck, The OkloNatural Reactors: Cumulative Fission Yieldsand Nuclear Characteristics of Reactor Zone 9,"Earth Planet. Sci. Lett. 89,193-206



N. A. Marley, P. S. Z. Rogers, T. M. Benjamin,and D. R. Janecky, "The Study of MetalSpeciation at High Temperatures and Pressuresvia Laser Raman Spectroscopy," Trans. Am.Geophys. Union 68 (44), 1538 (1987).

N. A. Marley, P. S. Z. Rogers, T. M. Benjamin,and D. R. Janecky, "Raman Spectroscopic Studyof Metal Speciation Under High Temperaturesand Pressures: Zinc Bromide and Zinc ChlorideSystems," in "Isotope and Nuclear ChemistryDivision Annual Report FY 1987, October 1986-September 1987," Los Alamos NationalLaboratory report LA-11291-PR (May 1988),pp. 110-113.

A. S. Mason, D. L. Finnegan, R. C. Hagan,R. Raymond, Jr., .K. Bayhurst, J. Mroz,C. L. Peach, and K. H. Wohletz, "Misty PictureAtmospheric Test," in "Isotope and NuclearChemistry Division Annual Report FY 1987,October 1986-September 1987," Los AlamosNational Laboratory report LA-11291-PR(May 1988), pp. 227-230.

A. Meijer, S. T. Kwon, and G. R. Tilton, "Pb-Sr-Nd Isotopic Studies on Ultramafic Nodules,"in Trans. Am. Geophys. Union 69, 502 (1988).

E. J. Mroz, M. Alei, A. S. Mason, and C. Cone,"Winter Haze Intensive Tracer Experiment,"in "Isotope and Nuclear Chemistry DivisionAnnual Report FY 1987, October 1986-September 1987," Los Alamos NationalLaboratory report LA-11291-PR (May 1988),pp. 230-231.

A. E. Norris, K. Wolfsberg, S. K. Gifford,H. W. Bentley, and D. Elmore, "Infiltrationat Yucca Mountain, Nevada, Traced by 36C1,"Nucl. Instr. and Methods B29, 376-379 (1987).

A. E. Ogard, J. L. Thompson, R. S. Rundberg,K. Wolfsberg, and H. W. Bentley, "Migration of36C1 from an Underground Nuclear Test," in"The University of Rochester Nuclear StructureResearch Laboratory 1987 Annual Report"(April 1988), p. 115.

A. E. Ogard, J. L. Thompson, R. S. Rundberg,K. Wolfsberg, P. W. Kubik, D. Elmore, andH. W, Bentley, "Why 36C1 Migrates FasterThan Tritium in Alluvium," in "Isotope andNuclear Chemistry Division Annual ReportFY 1987, October 1986-September 1987, L:os

Alamos National Laboratory reportLA-11291-PR (May 1988), pp. 121-124.

F. V. Perry, W. Scott Baldridge, and D. J.DePaolo, "Chemical and Isotopic Evidence forLithospheric Thinning Beneath the Rio GrandeRift," Nature 332 (6163), 432-434 (March 1988).

J. Rogowski, N. Kaffrell, H. Tetzlaff,N. Trautmann, D. De Frenne, K. Heyde,E. Jacobs, G. Skarnemark, J. Alstad,M. N. Harakeh, J. M. Schippers, S. Y. vander Werf, W. R. Daniels, and K. Wolfsberg,"Evidence for Shape Coexistence in Neutron-Rich Rh and Ag Nuclei," in Proceedings of theInternational Workshop on Nuclear Structureof the Zirconium Region," Bad Honnef,Germany, April 24-28,1988.

R. L. Tanner, A. H. Miguel, J. B. de Andrade,J. S. Gaffney, and G. E. Streit, 'AtmosphericChemistry of Aldehydes: Enhanced PeroxyacetylNitrate Formation from Ethanol-FueledVehicular Emissions," Environ. Sci. Tech. 22,1026-1034 (1988).

J. L. Thompson, Comp., and Ed., "Laboratoryand Field Studies Related to the RadionuclideMigration Project, October 1,1986-September30,1987," Los Alamos National Laboratoryreport LA-11223-PR (February 1988).

INCH

FY1986

W. B. N. Berry, P. Wilde, M. S. Quinby-Huntand C. J. Orth, "Trace Element Signatures inDictyonema Shales and their Geochemical andStratigraphic Significance," Norsk Geologist:Tidsskrift 66, 45-51 (1986).

R. R. Brooks, C. P. Strong, J. Lee, C. J. Orth,J. S. Gilmore, D. E. Ryan, and J. Holzbecher,"Stratigraphic Occurrences of IridiumAnomalies at Four Creatceous-TertiaryBoundary Sites in New Zealand," Geology 14,727-729(1986).

G. W. Butler, D. J. Vieira, J. M. Wouters,H. Wollnik, K. Vaziri, F. K. Wohn, andD. S. Brenner, "TOFI Spectrometer for DirectMass Measurements of Exotic Light Nuclei,"Proc. Symp. on Recent Advances in the Study


Appen dix: Publications

of Nuclei Off the Line of Stability, Chicago,September 1985, ACS Symposium Series 324,459(1986).

D. L. Clark, C.-Y. Wang, C. J. Orth, andJ. S. Gilmore, "Conodont Survival and LowIridium Abundances Across the Permian-Triassic Boundary in South China," Science 233,984-986 (1986).

D. W. Efurd, J. Drake, F. R. Roensch,J. H. Cappis, and R. E. Perrin, "Measurementof 237Np by SID Ionization Source," Intl. J.Mass Spectrom.Ion Proc. 74, 309,1986.

A. Fazely and L. C. Liu, "Neutrinoless Double b-Decay and its Relation to Pion Double ChargeExchange," Phys. Rev. Lett. 57, 968 (1986).

H. Gaggeler, W. Briichle, M. Briigger,K. J. Moody, M. Schadel, K. Slimmerer,G. Wirth, Th. Blaich, G. Herrmann,N. Hildebrand, J. V. Kratz, M. Lerch andN. Trautmann, W. R. Daniels, M. M. Fowler,D. C. Hoffman, K. Gregorich, D. Lee,G. T. Seaborg, R. Welch, and H. R. Von Gunten,"Actinide Yields from the Reactions of 40Ca and48Ca with 248Cm," J. Less-Common Metals 122,433-439,1986.

B. G. Giraud and L. C. Liu, "VariationalApproach to Pion-Nucleus Optical Potential,"J. Phys. G12,1189 (1986).

Q. Haider and L. C. Liu, "Hadron StaticProperties Calculated with Iterative One-GluonExchange in the Friedberg-Lee NontopologicalSoliton Model," II Nuovo Cimento 95A, 173(1986).

Q. Haider and L. C. Liu, "The Effect of Self-Consistent Treatment of One-Gluon Exchangein the Friedberg-Lee Nontopological SolitonModel," J. Phys. G12, L75 (1986).

Q. Haider and L. C. Liu, "Formation of an Eta-Mesic Nucleus," Phys. Lett. B172, 257 (1986).

D. Joyce, H. O. Funsten, B. J. Lieb, H. S. Plendl,J. Norton, C. E. Stronach, V. G. Lind,R. E. McAdams, O. H. Otteson, L. W. Swenson,C. Pillai, D. J. Vieira, and A. J. Buffa, "200 MeVp+-Induced Single Nucleon Removal from 24Mg,"Phys. Rev. C 34,1813 (1986).

L. C. Liu, Q. Haider, "Signature for the Existenceof Eta-Mesic Nucleus," Phys. Rev. C 34,1845 a986).

L. C. Liu, "Reply to Comment on Comparisonof Approximate Chiral-Dynamical p N \ ppNModels Used in A(p,2p) Calculations," Phys.Rev. C 34, 2351 (1986).

L. C. Liu and Q. Haider, "Eta-Mesic Nucleus:A New Nuclear Species?," Proc. 2nd Int. Conf.on Intersection Between Particle and NuclearPhysics, Lake Louise, July 1986, AIP Conf. Proc.150, 930 (1986).

D. Mauzerall, A. Ley, and J. A. Mercer-Smith,"Biosynthetic Porphyrins and the Origin ofPhotosynthesis," invited paper, SecondSymposium on Chemical Evolution and theOrigin and Evolution of Life, Moffett Field,California, Proceedings of the SecondSymposium on Chemical Evolution and theOrigin and Evolution of Life, NASA ConferencePublication 2425, D. L. DeVincenzi and P. A.Dufour, eds., 94 (1986).

G. R. McGhee, Jr., C. J. Orth, L. R. Quintana:

J. S. Gilmore, and E. J. Olsen, "GeochemicalAnalyses of the Late Devonian Kellwasser EventStratigraphic Horizon at Steinbruch Schmidt (F.R. G.)," in Lecture Notes in Earth Sciences, Vol.8, Global Bio-Events, O. Walliser, ed. (Springer-Verlag, Berlin, Heidelberg, 1986), pp. 219-224.

G. R. McGhee,. Jr., C. J. Orth, L. R. Quintana,J. S. Gilmore, and E. J, Olsen, "Late DevonianKellwasser Event Mass Extinction Horizon inGermany: No Geochemical Evidence for a Large-Body Impact," Geology 14, 776-779 (1986).

T. W. Newton, D. E. Hobart, and P. D. Palmer,"The Formation of Plutonium(IV)-Colloid by theAlpha-Reduction of Pu(V) or Pu(VI) in AqueousSolutions," Radiochim. Ada 39,139-147 (1986).

C. J. Orth, L. R. Quintana J. S. Gilmore,R. C. Grayson, Jr., and E. H. Westergaard,"Trace-Element Anomalies at the Mississippian-Pennsylvanian Boundary in Oklahoma andTexas," Geology 14, 986-990 (1986).

C. J. Orth, L. R. Quintana, J. S. Gilmore andP. M. Sheehan, "Terminal Ordovician Extinction:Geochemical Analysis of the Ordovician-SilurianBoundary, Anticosti Island, Quebec," Geology 14,433-436 (1986).



C. Pillai, L. W. Swenson, D. J. Vieira,G. W. Butler, J. M. Wouters, S. H. Rokni,K. Vaziri, and L. P. Remsberg, "Direct MassMeasurements in the Light Neutron-RichRegion Using a Combined Energy and Time-of-Flight Technique," Proc. Int. Conf. on NuclearData for Basic and Applied Science, Santa Fe,May 1985, Radiation Effects 96,1383 (1986).

W. L. Talbert, Jr. and M. E. Bunker,"Possibilities for Studying Short-Lived Nucleiat LAMPF," Proc. Int. Conf. on Nuclear Datafor Basic and Applied Science, Santa Fe, May1985, Radiation Effects 96,1303 (1986).

W. L. Talbert, Jr. and M. E. Bunker, "PotentialCapabilities at LAMPF to Study Nuclei FarFrom Stability," Proc. Symp. on RecentAdvances in the Study of Nuclei Off the Line ofStability, Chicago, Sept. 1985, ACS SymposiumSeries 324, 426 (1986).

W. L. Talbert, Jr. and M. E. Bunker, "FutureDirections and Emerging Techniques for ISOLSystems," Proc. Int. Conf. on Nuclei Off the Lineof Stability, Dubrovnik, June 1986, Eds. R. A.Meyer and V. Paar (World Scientific Publ.,Singapore, 1986), pp. 645-657.

D. J. Vieira, J. M. Wouters, K. Vaziri,R. H. Kraus, Jr., H. Wollnik, G. W. Butler,F. K. Wohn, and A. H. Wapstra, "Direct MassMeasurements of Neutron-Rich Light NucleiNear N=20," Phys. Rev. Lett. 57, 3253 (1986).

P. M. Wanek, F. J. Steinkruger, and D. C. Moody,"Separation of 109mAg from 109Cd: A BiomedicalGenerator?," Proceedings of the FifthSymposium on Nuclear Chemistry,Radiochemistry and Radiation Chemistry,Guanajuato, Mexico, December 1984, p. 63(1986).

P. Wilde, W. B. N. Berry, M. S. Quinby-Hunt,C. J. Orth, L. R. Quintana, and J. S. Gilmore,"Iridium Abundances Across the Ordovician-Silurian Stratotype," Science 233, 339-341(1986).

D. A. Wrobleski, R. R. Ryan, H. J. Wasserman,K. V. Salazar, R. T. Pain, and D. C. Moody,"Synthesis and Characterization ofBis(diphenylphosphido)bis(pentamethylcyclopentadienyl; Thorium(IV), [(h5-C5(CH3)5]2

Th(PPh2)2," Organometallics 5, 90 (1986).

FY1987

M. Alei, J. H. Cappis, M. M. Fowler, D. J. Frank,M. Goldblatt, P. R. Guthals, A. S. Mason,T. R. Mills, E. J. Mroz, T. L. Norris, R. E. Perrin,J. Poths, D. J. Rokop, and W. R. Shields,"Determination of Deuterated Methanes forUse as Atmospheric Tracers," AtmosphericEnvironment, Vol. 21, No. 4, pp. 909-915,1987.

S. M. Bowen, T. J. Beugelsdijk, andG. W. Knobeloch, "Nevada Test Site SolutionDispensing Robotics System," in Advancesin Laboratory Automation Robotics, 1986,J. R. Strimaitis and G. L. Hawk, Eds.(Zymark Corporation, Hopkinton, 1987),pp. 347-352.

T. P. Burns and R. D. Rieke, "Highly ReactiveMagnesium and Its Application to OrganicSyntheses," J. Org. Chem. 52, 3674-3680,1987.

H. W. Baer, M. J. Leitch, R. L. Burman,M. D. Cooper, A. Z. Cui, B. J. Dropesky,G. C. Giesler, F. Irom, C. J. Morris,J. N. Knudson, J. R. Comfort, D. N. Wright,and R. Gilman, "Double-Analog Transition48Ca(p+,p-)48Ti at 35 and 50 MeV," Phys.Rev. C 35,1425 (1987).

D. A. Cole, J. A. Mercer-Smith, F. J. Steinkruger,W. A. Taylor, M. R. Moragne, S. A. Schreyer, andD. K. Lavallee "Imaging Inflamed Lymph Nodeswith a 67Cu-Labeled Porphyrin," "Preparationand Characterization of 67Cu-LabeledAntibodies," Progress at LAMPF January-December 1986 (J. C. Allred and B. Talley, eds.),Los Alamos National Laboratory ProgressReport LA-11048-PR, pp. 151-154 (1987).

A. Fazely and L. C. Liu, "Reply to Comment onNeutrinoless Double-Beta Decay and PionDouble Charge Exchange," Phys. Rev. Lett. 59,2384 (1987).

G. Fiege, D. Molzahn, R. Brandt, D. C. Hoffman,S. J. Knight, A. J. Gancarz, G. W. Knobeloch,and G. O. Lawrence, "Search for TransuraniumActinides in Atlantis II Hot Brines,"Radiochim. Acta 41, 55-56 (1987).

M. M. Fowler, P. Laysaght, and J. B. Wilhelmy,"The Accelerator-Based Mass Spectrometry ofMethane,' Nucl. Instru. and Meth. in Phys. Res.B24/25, 672-675,1987.



B. G. Giraud, S. Kessal, and L. C. Liu, "DoorwayStates Induced by Quantum Recoils," Phys.Rev.C 35,1844(1987).

Q. Haider and L. C. Liu, "Nuclear Bound Statesof the h Meson and Pion Double ChargeExchange Reactions, Phys. Rev. C 36,1636(1987).

J. Herrmann, N. T. Porile, B. J. Dropesky, andG. C. Gielser, "Recoil Study of the Spallation ofGold by Intermediate Energy Pions," Phys. Rev.C 35,1823(1987).

M. A. C. Hotchkis, J. E. Reiff, D. J. Vieira,F. Blonnigen, T. F. Lang, D. M. Moltz, X. Xu,and J. Cerny, "Beta-Delayed Proton Decay of61Ge," Phys. Rev. C 35, 315 (1987).

J. R. Hurd, J. S. Boswell, R. C. Minehart,Y. Tzeng, H. J. Ziock, K. O. H. Ziock, L. C. Liu,and E. R. Siciliano, "The Reaction (p+,p+d) on6Li and 12C," Nucl. Phys. A475, 743 (1987).

D. R. Janecky, R. S. Rundberg, M. A. Ott, andA. J. Mitchell "Update Report on Fracture Flowin Saturated Tuff: Dynamic Transport Task forthe Nevada Nuclear Waste StorageInvestigations Project," Los Alamos NationalLaboratory YMP Milestone Report R347(April/1987).

N. Kaffrell, J. Rogowski, H. Tetzlaff,N. Trautmann, D. DeFrenne, K. Heyde,E. Jacobs, G. Skarnemark, J. Alstad,M. N. Harakeh, J. M. Schippers, S. Y. van derWerf, W. R. Daniels, and K. Wolfsberg,"Evidence for Shape Coexistence in Neutron-Rich Ru and Ag Isotopes," in Proceedings ofthe Fifth International Conference on NucleiFar From Stability, September 14-19,1987,Rosseau Lake, Ontario, Canada (1987).

G. Keller, S. L. DHondt, C. J. Orth,.P. Q. Oliver,E. M. Shoemaker, and E. Molina, "Late EoceneMicrospherules: Stratigraphy, Age andGeochemistry," Meteoritics 22, 25-61 (1987).

L. Liepins and K. W. Thomas, "Summary ofl^C Literature Relevant to a Geologic WasteRepository," Nucl. Waste Mgmt amd the NuclFuel Cycle, Vol. 9 (1-4; p. 1-24 Q987).

J. A. Mercer-Smith, J. C. Roberts, S. D. Figard,and D. K. Lavallee, "The Development of

Copper-67 Labeled Porphyrin-AntibodyConjugates," Antibody-Mediated DeliverySystems, Vol. 1 of Targeted Diagnosis andTherapy Series (J, T. Rodwell, edj, MarcelDekker, NY, pp. 317-352 (1987).

J. A. Mercer-Smith, D. A. Cole, J. C. Roberts,D. R. Phillips, R. C. Staroski, W. A. Taylor,S. D. Figard, W. L. Anderson, andD. K. Lavallee, "Preparation of 67Cu-LabeledKadiopharmaceuticals," Progress at LAMPFJanuary-December 1986 (J. C. Allred andB. Talley, eds.), Los Alamos National LaboratoryProgress Report LA-11048-PR, p. 145 (1987).

K. J. Moody, W. Briichle, M. Briiugger,H. Gaggler, B. Haefner, M. Schadel, andK. Siimmerer, H. Tetzlaff, G. Herrmann,N. Kaffrell, J. V. Kratz, J. Rogowski,N. Trautmann, M. Skalberg, G. Skarnemark,J. Alstad, and M. M. Fowler, "New Nuclides:Neptunium-243 and Neptunium-244," Z. Phys.A —Atomic Nuclei 328, 417-422,1987.

D. E. Morris and D. E. Hobart, "VoltammetricInvestigation of the CeriumdV/III) RedoxCouple in Aqueous Carbonate Media," Lan. Act.Res. 2, 91-103 (1987).

C. J. Orth, "Mass Extinctions: A Search forCauses," Los Alamos Technical Bulletin, LALP-87-28 (1987).

C. J. Orth, J. S. Gilmore, and J. D. Knight,"Indium Anomaly at the Cretaceous-TertiaryBoundary in the Raton Basin," in New MexicoGeological Society Guidebook, 38th FieldConference, Northeastern New Mexico,S. G. Lucas and A. P. Hunt, eds. Universityof New Mexico Printing Plant, 1987)pp. 265-270.

J. C. Peng, J. Kapustinsky, C. Lee, M. J. Leitch,T. K. Li, L. C. Liu, J. M. Moss, J. E. Simmons,S. M. Tang, C. Smith, and R. R. Whitney,"Observation of h-Meson Production in theReaction p-+3He \ t," Phys. Rev. Lett. 58, 2027(1987).

D. R. Phillips, D. C. Moody, W. A. Taylor,N. J. Segura, and B. D. Pate, "ElectrolyticSeparation of Selenium Isotopes from ProtonIrradiated RbBr Targets, Int. J. Appl. Rad.Isotopes 38, 521 a 98 7).

Isotope and Xuclear Chemistry Division Report 1988 35


R. D. Rieke, T. P. Burns, R. Wehmeyer, B. Kahn,"Preparation of Highly Reactive Metal Powders:Some of Their Uses in Organic andOrganometallic Chemistry," in "High EnergyProcesses in Organometallic Chemistry,"K. S. Suslick, ed. American Chemical SocietySymposium Series, 333, 223-245,1987.

J. C. Roberts, J. A. Mercer-Smith, W. A. Taylor,R. C. Staroski, D. R. Phillips, S. D. Figard,W. L. Anderson, and D. K. Lavallee,"Preparation and Characterization of 67Cu-Labeled Antibodies," Progress at LAMPFJanuary-December 1986 (J. C. Allred andB. Talley, eds.), Los Alamos National LaboratoryProgress Report LA-11048-PR, pp. 146-150 (1987).

J. C. Roberts, S. D. Figard, J. A. Mercer-Smith,Z. V. Svitra, W. L. Anderson, and D. K. Lavallee,"Preparation and Characterization of Copper-67Porphyrin-Antibody Conjugates," Journal ofImmunological Methods, 105,153-164 (1987).

R. S. Rundberg, D. R. Janecky, andA. J. Mitchell, "Anion Exclusion in YuccaMountain Tuff," Los Alamos NationalLaboratory YMP Milestone Report R313(January/1987).

R. S. Rundberg, "Assesment Report on theKinetics of Radionuclide Adsorption onYucca Mountain Tuff," Los Alamos NationalLaboratory Report LA-11026-MS (July/1987).

R. S. Rundberg, I. Partom, M. A. Ott,A. J. Mitchell, and K. Birdsell "Diffusionof Nonsorbing Tracers in Yucca MountainTuff," Los Alamos National Laboratory YMPMilestone Report R524 (November/1987).

C. P. Strong, R. R. Brooks, S. M. Wilson,R. D. Reeves, C. J. Orth, X.-Y. Mao,L. R. Quintana, and E. Anders, "A NewCretaceous-Tertiary Boundary Site atFlaxbourne River, New Zealand: Biostratigraphyand Geochemistry," Geochim. et Cosmochim.Ada 51, 2769 (1987).

W. L. Talbert, Jr., M. E. Bunker, andJ. W. Starner, "Optimization of a He-jetActivity Transport System to Use at LAMPF,"Proc. 11th Int. Conf. on Electromagnetic IsotopeSeparators and Techniques Related to TheirApplication, Los Alamos, August 1986, Nucl.Instr. andMeth. B 26, 345 (1987).

W. L. Talbert, Jr., H. Wollnik, and C. Geissee,"Ion Optical Design for an On-Line MassSeparator at LAMPF," Proc. 11th Int. Conf.on Electromagnetic Isotope Separators andTechniques Related to Their Application, LosAlamos, August 1986, Nucl. Instrum. Meth, B26, 351 (1987).

W. L. Talbert, Jr. and M.E. Bunker, "FutureDirections and Emerging Techniques for ISOLSystems," in Nuclear Structure, Reactions, andSymmetries Vol. 2, R. A. Meyer and V. Paar,Eds. (World Scientific, Singapore, 1987).

K. W. Thomas, "Summary of SorptionMeasurements Performed with Yucca Mountain,Nevada, Tuff Samples and Water from Well J-13," LA-10960-MS, Dec. 1987.

J. L. Thompson, Ed., "Laboratory and FieldStudies Related to the Radionuclide MigrationProject, October 1,1985 - September 30,1986,"Los Alamos National Laboratory report,LA-11081-PR (1987).

I. R. Triay and R. S. Rundberg, "Determinationof Selectivity Coefficient Distributions byDeconvolution of Ion-Exchange Isotherms,"Journal of Physical Chemistry, 91, 5269-74(1987).

K. Vaziri, F. K. Wohn, D. J. Vieira, H. Wollnik,and J. M. Wouters, "Performance of theReaction-Product Transport Line Associatedwith the TOFI Spectrometer," Nucl. Instr. andMeth. B26, 280 (1987).

H. Wollnik, J. M. Wouters, and D. J. Vieira,"TOFI—An Isochronous Time-of-Flight MassSpectrometer," Nucl. Instr. andMeth. A258, 331(1987).

J. M. Wouters, D. J. Vieira, H. Wollnik,G. W Butler, R. H. Kraus, Jr., and K. Vaziri,"The Time-of-Flight Isochronous (TOFI)Spectrometer for Direct Mass Measurementsof Exotic Light Nuclei," Nucl. Instr. and Metk.B26, 286 (1987).

FY1988

M. Attrep, Jr., D. W. Efurd, and F. R. Roensch,"Development of a Rapid RadiochemicalProcedure for the Separation of 235m|jfrom 239Pu," in Essays in Nuclear, Geo- and

96 Isotope and-Nuclear Chemistry Division Annual Report FY 1988

l'ubU<-(itu>iis

Cosmochemistry, ed. by M. W. RoweiBethwether Press, 1988).

R. Beckman, B. Crowe, and K. Thomas,"Preliminary Report on the StatisticalEvaluation of Sorption Data: Sorption as aFunction of Mineralogy, Temperature, Time,and Particle Size," LA-11246-MS, May, 1988.

H. C. Britt, D. J. Fields, L. Hansen, R. G. Lanier,R. R. Marquardt, B. A. Remington,D. Massoletti, N. Namboordiri, T. C. Sangster,G. Struble, M. Webb, T. Blaich, M. Fowler,J. Wilhelmy, B. Dichter, S. Kaufman,F. Videbaek, Y. D. Chan, A. Ducal, A. Harmon,J. Pouliot, and R. Stokstad, "Studies ofFragmentation at 100 MeV/A at the BevalacLow Energy Beam Line," to be published inthe Proceedings of the Lawrence BerkeleyLaboratory, Eighth High Energy Heavy IonStudy, November 16-20,1987, LBL-24580,pp. 343-351 (1988).

D. A. Cole, J. A. Mercer-Smith, K. Williams,J. Norman, S. A. Schreyer, and D. K. Lavallee,"The Localization of 67Cu-Labeled 5,10,15,20-Tetrakis(4-Carboxyphenyl; Porphinato Copper(II) by Inflamed Lymph Nodes," Progress atLAMPF January-December 1987 (K Poelakker,ed.), Los Alamos National Laboratory ProgressReport LA-11339-PR, pp. 174-177 (1988).

P. M. Grant, B. R. Erdal, R. E. Whipple anH. A. O'Brien, Jr., "Medium-Energy SpallationCross Sections-3. Vanadium Irradiation with800-MeV Protons," Appl. Radiat. Isot. Vol. 39,No. 6, pp. 501-502,1988, Int. J. Radiat. Appl.Instrum. Part A.

A. H. Herring, R. M. Lopez, D. C. Moody,C. P. Padilla, K. E. Peterson, D. R. Phillips,F. H. Seurer, R. C. Staroski, F. J. Steinkruger,and W. A. Taylor, INC-11 Radioistope ProductionActivities," Progress at LAMPF January-December 1987 (K. Poelakker, ed.), Los AlamosNational Laboratory Progress Report LA-11339-PR, pp. 181-184 a 988).

P. E. Koehler, C. D. Bowman, F. J. Steinkruger,D. C. Moody, G..M. Hale, J. W. Starner,S. A. Wender, R. C. Haight, P. W. Lisowski,and W. L. Talbert, "7Befn,p;7Li Total CrossSection from 25 meV to 13.5 keV," PA vs.Rev. C 37, pp. 917-926 (1988»..

R. H. Kraus, Jr., D. J. Vieira, H. Wollnik,and J. M. Wouters, Large-A tea Fast-TimingDetectors Developed for ihe TOFISpectrometer," Nucl. lustr. andMeth.A264, 327 (1988 >.

G. Mamane, E. Chaifetz, E. Dafni, A. Zemel,and J. B. Wilhelmy, "Lifetime Measurementsof Excited Levels in Prompt Fission Productsof 252Cf," Nucl. Phys. A454, 213 (1988;.

The Medical Radioisotopes Research Program,"Radioisotopes Research,' Los Alamos TechnicalBulletin LALP-87-37 (January 1988).

D. E. Morris and D. E. Hobart, "Raman Spectraof the Lanthanide Oxalates," J. RamanSpectrosc. 19, 231-238 (1988).

A. E. Ogard, J. L. Thompson, R. S. Rundberg,K. Wolfsberg, and H. W. Bentley, "Migration of36C1 from an Underground Nuclear Test," in"The University of Rochester Nuclear StructureResearch Laboratory 1987 Annual Report"(April 1988), p. 115.

C. J. Orth, M. Attrep, Jr., X.-Y. Mao,E. G. Kauffman, R. Diner, and W. P. Elder,"Iridium Abundance Maxima in the UpperCenomanian Extinction Interval," Geophys.Res. Lett. 15 (4), 346 (1988).

C. J. Orth, L. R. Quintana, J. S. Gilmore,J. E. Barrick, J. N. Haywa, andS. A. Spesshardt, "Pt-Group MetalAnomalies in the Lower Mississippian ofSouthern Oklahoma," Geology 16, 627 1988,1.

D. R. Phillips, F. J. Steinkruger, andR. C. Staroski, "Recovery of +*Ti and 26A1from LAMPF Beamstop, Progress at LAMPFJanuary-December 1987 (K. Poelakker, ed. j ,Los Alamos National Laboratory ProgressReport LA-11339-PR, pp. 185-187 (19881.

J. C. Roberts, J. A. Mercer-Smith,S. A. Schreyer, R. C. Staroski, W. A. Taylor,V. A. Lennon, and D. K. Lavallee, PotentialTherapy for Myasthenia Gravis: Radiolabelingan Antigenic Fragment of the HumanAcetylcholine Receptor with 67Cu," Progressat LAMPF January-December 1987< K. Poelakker, ed. >, Los Alamos NationalLaboratory Progress Report LA-11339-PR,pp. 178-180(1988).

Isotope and Nuclear Chvmistry Dtiisum Report W88 97


J. C. Roberts, J. A. Mercer-Smith,S. A. Schreyer, D. R. Phillips, R. D. Staroski,W. A. Taylor, W. L. Anderson, and D. K. ^Lavallee, "Further Characterization of ^Cu-Labeled Porphyrin-Antibody Conjugates,"Progress at LAMPF January-December 1987(K. Poelakker, Ed.), Los Alamos NationalLaboratory Progress Report LA-11339-PR,pp. 168-173 (1988).

R. S. Rundberg, D. R. Janecky, M. Ott, andA. Mitchell, "Dynamic Transport of ColloidalTracers through Fractured Tuff: 0.10- to 9.55-mm-Diameter Carboxylated PolystereneSpheres," Los Alamos National LaboratoryYMP Milestone Report R743 (May/1988).

R. S. Rundberg, A. J. Mitchell, I. R. Triay,and B. J. Torstenfelt, "Size and Density of a242Pu Colloid," In "Scientific Basis for NuclearWaste Management XI;" M. J. Apted andR. E. Westerman, Eds.; Material ResearchSociety Symposium Proceedings: Pittsburgh,1988; Vol. 112, p. 243-248.

C. P. Strong, R. R. Brooks, C. J. Orth, andX.-Y. Mao, "An Iridium-Rich CalcareousClaystone (Cretaceous-Tertiary Boundary)from Wharanui, Marlborough, New Zealand,"New Zealand J. of Geology andGeophys. 31,191 (1988).

Thompson, J. L., Comp. and Ed., "Laboratoryand Field Studies Related to the RadionuclideMigration Project, October 1.1986 - September30,1987," Los Alamos National Laboratoryreport LA-11223-PR (February 1988).

I. R. Triay and R. S. Rundberg, "Deconvolutionof Ion-Exchange Isotherms," Los AlamosNational Laboratory YMP Milestone ReportR720 (September/1988).

A. Turler, F. Wegmuller, H. R. Von Gunten,K. E. Gregorich, D. Lee, D. C. Hoffman, andM. M. Fowler, "Fast Radiochemical Separationof Am, Pu, Np, U, Pa, Th, Ac and Ra in HeavyIon Reactions with Actinide Targets,"Radiochimica Acta 43,149-152,1988.

L. E. Ussery, D. J. Vieira, J. J. H. Berlijn,G. W. Butler, B. J. Dropesky, G. C. Giesler,N. Imanishi, M. J. Leitch, and R. S. Rundberg,"Excitation Function for the Pion Single-Charge-

Exchange Reaction 13C(p+,p0)13N(g.s.),"Phys. Rev. C38, 2761 (1988).

F. Videbaek, B. Dichter, S. Kaufman, O. Hansen,M. J. Levine, C. E. Thorn, W. Trautman,J. Boissevan, T. Blaich, M. Fowler, A. Gavron,B. Jacak, P. Lysaght, J. Wilhelmy, H. C. Britt,R. L. Ferguson, G. Westfall, D. Cobra,G. Mamane, andZ. Frankel, "Fission Inducedby Peripheral Reactions with Fe-56 Plus Au-197at 100 MeV/u," Proceedings of the LawrenceBerkeley Laboratory Eigth High Energy HeavyIon Study, November 16-20,1987, LBL-24580pp. 333-342, (1988).

D. J. Vieira, J. M. Wouters, and the TOFICollaboration, "Direct Mass Measurements ofLight Neutron-Rich Nuclei Using Fast RecoilSpectrometers," AIPConf. Proc. 164,1 (1988).

W. S. Wolbach, I. Gilmour, E. Anders, C. J. Orth,and R. R. Brooks, "Global Fire at theCretaceous-Tertiary Boundary," Nature 334,665 (1988).

Patents

P. M. Wanek, F. J. Steinkruger, and D. C. Moody,"Biomedical Silver-109m Isotope Generator,"United States Patent, Number 4,664, 892,May 12,1987.

98 Isotope and Nuclear Chemistry Division Annual Report FY 198S

,\f>]H'rtri>\;

Presentations

INC-4

K. D. Abney, "Reaction Chemistry of theActinido Metals, Oxides, and Fluoridesin Superacid Media," seminar, LawrenceLivermore National Laboratory, Livermore,California, July 19,1988. Invited.

K .D. Abney, "Reaction Chemistry of theActinide Metals, Oxides, and Fluorides inSuperacid Media," seminar, SavannahRiver Laboratory, Aiken, South Carolina,April 19,1988. Invited.

K. D. Abney, P. G. Eller, L. B. Asprey,S. A. Kinkead, E. M. Larson, L R. Avens,C. F. Pace, and W. H. Woodruff, "ReactionChemistry of Uranium and Thorium Metals,Oxides and Fluorides in Superacid Media,"ACS Spring Meeting, Toronto, Canada,June 5-10,1988.

K. D. Abney, P. G. Eller, M. P. Eastman,W. H. Woodruff, C. F. Pace, and S. A. Kinkead,"Kinetic Investigation of Dioxygendifluoride(FOOF)," 12th International Symposium onFluorine Chemistry, Santa Cruz, California,August 7-12,1988.

S. F. Agnew and B. I. Swanson "VibrationalSpectroscopy at Extreme Pressure," GordonConference on Vibrational Spectroscopy,Brewster Academy, Wolfeboro, New Hampshire,August 15-19,1988. Invited.

S. F. Agnew and B. I. Swanson, "Reactionsunder Extreme Conditions: Decompo-sition ofNitromethane and Nitric Oxide at Very HighPressure," Gordon Conference on EnergeticMaterials, New Hampton, New Hampshire,June 24,1988. Invited.

S. F. Agnew, "FTIR Spectroscopy and HighPressure: (aj SF6 in Xe at High Pressure;(b) Analysis of High Pressure and HighTemperature CH3NO2 Reaction Products,"Technical Discussions at CLS-4 GroupMeetings, December 3,1987.

S. F. Agnew, "Pressure Dependence of ElectronicAbsorption Spectra," Western SpectroscopyAssociation, 35th Annual Conference on Modern

Spectroscopy, Asilomar, Pacific Crow.California, January 20-22. 1988. Poster.

S. F. Agnew, "Seismosauras of San Vsidro: II.Dinosaur Fossils as Experiments in Long-termMineral Migration," l"SV Division Colloquium.November 19.1987.

S. F. Agnew, "Spcctroscopy at High Pressure:Model for Predicting Density Dependence ofElectronic Absorption Bands," PhysicsDepartment, Washington State University.Pullman, Washington, October 13,1987.Invited colloquium.

S. F. Agnew and M. Aldissi, "Resonance RamanExcitation Profiles of Polyacetylene/PolyisopreneBlock Co-Polymers in Toluene," InternationalConference on Science and Technology ofSynthetic Metals, Santa Fe, New MexicoJune 26-July 2,1988.

S. F. Agnew and B. I. Swanson, "FTIRSpectroscopy and High Pressure: (a) SF6 inXenon at High Pressure, (b) Analysis of HighPressure/High Temperature NitromethaneReaction Products," Symposium on FT-IRSpectroscopy, 9th Rocky Mountain RegionalMeeting, ACS, Las Vegas, Nevada, March 27-30,1988. Invited.

S. F. Agnew and B. I. Swanson, "FTIRSpectroscopy and High Pressure: SF6 inXenon at High Pressure, (b) Analysis of HighPressure / High Temperature NitromethaneReaction Products," Digilab Workshop onNew Techniques, Albuquerque, New Mexico,April 8,1988. Invited.

S. F. Agnew, B. I. Swanson, D. Pettit, andJ. Dick, "Conversion of N2O4 to NO+NO3-with Shock Loading and Static Loading,"Shock Wave Symposium to honor GeorgeDuvall, Washington State University,Pullman, Washington, September 1,1988.

S. P. Armes, M. Aldissi, and S. F. Agnew,"Poly(vinyl-pyridine)-based Stabilizers forAqueous Polypyrrole Latices," InternationalConference on Science and Technology ofSynthetic Metals, Santa Fe, New Mexico,June 26-July 2,1988,

1 and Nuclear VkamisWv Dii isi<m Avtuml l\c;mr' ]•")'

Appendix: Presentations

L. R. Avens, K. D. Abney, E. M. Larson, andP. G. Eller, "Chemistry, Thermal Decomposition,and Crystal Structure of HydroniumHexafluoroantimonate," ACS SpringMeeting, Toronto, Canada, June 5-10,1988.

L. R. Avens and P. G. Eller, "Low TemperatureFluorination of Actinides," 1987 Winter Meeting,American Nuclear Society, Los Angeles,California, November 15-19,1987.

J. R. Brainard and S. Edmondson, "Structure ofthe Signal Sequence from Yeast MitochondrialSuperoxide Dismutase," American Society forBiochemistry and Molecular Biology, Las Vegas,Nevada, May 1-5,1988.

C. J. Burns, R. R. Ryan, and A. P. Sattelberger,"Disproportionation of Uranyl Alkoxides,"Eighteenth Rare Earth Research Conference,Lake Geneva, Wisconsin, September 12-16,1988.

C. J. Burns, W. H. Smith, R. R. Ryan, andP. Sattelberger, "High Valent OrganouraniumComplexes: Synthesis, Characterization andReactivity," ACS Spring Meeting, Toronto,Canada, June 5-10,1988.

S. D. Conradson, "Recent Developments inX-Ray Absorption Spectroscopy at Los Alamos,"INC Division Colloquium, Los Alamos, April 21,1988.

S. D. Conradson, "X-ray AbsorptionSpectroscopy of Elements of Z < 10 Using aFree-Electron Laser Source," Optical Societyof America topical meeting on Free-ElectronLaser Applications in the Ultraviolet,Cloudcroft, New Mexico, March 2-5,1988.

S. D. Conradson, "XAS Studies of 1-2-3Materials as a Function of Temperatureand Chemical Modifications," FORUM onHigh Temperature Superconductivity,CMS Division, September 14,1988.

S. D. Conradson, M. A. Stroud, andB. I. Swanson, "Pressure Tuning of the 1-DMixed-Valence SolidK4[Pt2(P2O5H2)4Br].nH2O from a Charge-Density-Wave to a Valence-Delocalized GroundState," American Physical Society GeneralMeeting, New Orleans, Louisiana, March 21-25,1988.

P. K. Dorhnut. P. f>. Kller. A. li. K11RH. J. Ki.-sanc. and W. H. Woodruff."Intercalation of Acliny] Jons into HydrogenActinyl Phosphate Host Lattices: Uranyl andNeptunyl Compounds," Eighteenth Rare- EarthResearch Conference, Lake Geneva, Wisconsin,September 12-16, 1988.

M. P. Eastman, P. G. Eller, K. D. Abney.W. H. Woodruff, C. F. Pace. S. A. Kinkead.R. C. Kennedy, and R. J. Kissane, Gas PhaseStability of Dioxygendiiluoride.' ACS SpringMeeting, Toronto. Canada, June 5-10,1988.

P. G. Eller, "Superoxidizer/superacidChemistry," Chemistry Department,University of Wisconsin, Madison,Wisconsin, October 12,1987.

P. G. Eller, "Superoxidizer/superacid Chemistry,"Department of Chemistry, University of HawaiiInvited seminar.

P. G. Eller, "Superoxidizer/SuperacidChemistry," Monash University, Clayton,Victoria, Australia, March 11,1988.

P. G. Eller, "Superoxidizer/superacid Chemistry,"University of Melbourne. Melbourne. Australia,April 27,1988.

L. Esserman and S. D. Conradson,"Potential Medical Applications of UVFree-Electron Lasers," Optical Society ofAmerica topical meeting on Free-Electron ILaser Applications in the Ultraviolet,Cloudcroft, New Mexico, March 2-5,1988.

J.A. Fee, "Some Old Problems in Bio-InorganicChemistry" Revelations from the Study ofThermophilic Bacteria," Spring Seminars,Chemistry Department, University ofNew Mexico, Albuquerque, New Mexico,February 26,1988.

P. J. Hay and E. M. Kober, "Ab Initio Studiesof Transition-Metal Dihydrogea Chemistry,"Symposium on the Interplay of Theory andExperiment in Organometallic Chemistry,March 28,1988.

P. J. Hay and E. M. Kober, Ab Initio Studioof Transition-Metal Dihydrogen Chemistry,"ACS Spring Meeting, Toronto, Canada,June 5-10,1988.

Isotope and Nuclear Chemistry Division Annual Report FY ]988

D. R. Houck, J. L. Hanners, C. J. Unkefer.M.A.G. van Kleef, and J. A. Duine, "PQQ:Biosynthetic Studies in MethylbacteriumAMI and Hyphomicrobium X Using Specific13C Labeling and NMR," 1st InternationalSymposium on PQQ and Quinoproteins, Delft,The Netherlands, September 5-7,1988.

D. R. Houck and C. J. Unkefer, "13C and 1HNMR studies of PQQ and Selected Derivatives,"1 st International Symposium on PQQ andQuinoproteins, Delft. The Netherlands,September 5-7, 1988.

G. D. Jarvinen, R. R. Ryan B. F. Smith,W. H. Smith, and D. D. Ensor, "ComplexationStudies of Soft Donor Ligands," 12th ActinideSeparations Conference, Naperville, Illinois,May 8-11. 1988. Invited.

B. S. Jorgensen, M. Aldissi, R. Liepins, andS. F. Agnew, "Highly Oriented UnsubstitutedPolydiacetylene," The Materials ResearchSociety 1987 Fall Meeting, Boston,Massachusetts, November 30-December 5,1987.

G.R.K Khalsa, C. J. Unkefer,G. J. Kubas, andR. R. Ryan, "Investigation of the Dihydrogen-Dihydride Equilibrium, W(CO)3(PR3)2(h2-H2)<--> WH2(CO)3(PR3)2," ACS Spring Meeting,

Toronto, Canada, June 5-10,1988.

R. J. Kissane, P. G. Eller, S. A. Kinkead,T. R. Mills, J. D. Purson, and R. C. Kennedy,"Synthesis and Handling of DixoygenDifluoride," Technicians Session, 9th RockyMountain Regional Meeting, ACS, Las Vegas,Nevada, March 27-30,1988.

T. J. Knight, C. Sengupta-Gopalan, andP. J. Unkefer, "Oats Tolerant of Pseudomonassyi'ingae pv. tabaci Contain TbL-insensitiveLeaf Glutamine Synthetases," Annual Meeting,Southwest Consortium on Plant Genetics,Las Cruces, New Mexico, April 17-20,1988.

T. J. Knight, R. Dickstein, C. Sengupta-Gopalan,and P. J. Langston-Unkefer, "Enhancement ofSymbiotic N2 Fixation," InternationalSymposium on Plant Nirtrogen Metabolism,Annual Meeting of the Phytochemical Societyof North America, Iowa City, Iowa, June 26-30,1988.

G. J. Kubas, "Coordination of HydrogenMolecules to Metal Centers: Prototype forNon-Classical Chemical Bonding," INCDivision colloquium, January 21,1988.

G. J. Kubas, "Molecular Hydrogen Coordinationto Transition Metals," Department* s) ofChemistry at Northwestern University,Evanston, Illinois, November 5,1987, andUniversity of Chicago, Chicago, Illinois,November 6,1987. Invited seminars.

G. J. Kubas, C. J. Unkefer, and G.R.K. Khalsa."Molecular Hydrogen Coordination to Ti'ansitionMetal Complexes," Symposium on the Interplayof Theory and Experiment in OrganometallicChemistry, March 28,1988.

G. J. Kubas, J. Eckert, L. S. Van Der Sluys,P. J. Vergamini, R. R. Ryan, and G.R.K. Khalsa," Dynamics in Binding of Molecular HydrogenLigands," ACS Spring Meeting, Toronto,Canada, June 5-10,1988.

P. J. Langston-Unkefer, "A Microbe-MediatedEnhancement of Symbiotic Nitrogen Fixation,"Department of Plant Pathology, Michigan StateUniversity, East Lansing, Michigan, December21,1987.

P. J. Langston-Unkefer, "A Microbe-MediatedEnhancement of Symbiotic Nitrogen Fixation,"Division of Biology and Biomedical Sciences,Plant Biology Program, Washington University,St. Louis, Missouri, October 28,1987.

P. J. Langston-Unkefer, "AssimilationofNitrogen," Guest Lecturer in the BiologyDepartment, Visiting Seminar Series onNitrogen Metabolism, Washington University,St. Louis, Missouri, October 27,1987.

P. J. Langston-Unkefer, "Molecular Basis of aMicrobe-Mediated Enhancement of SymbioticNitrogen Fixation," Plant BiochemistryColloquium speaker, University of Missouri,Columbia, Missouri, October 15,1987.

P. J. Langston-Unkefer, T. J. Knight, andC. Sengupta-Gopalan, "A Microbe-MediatedEnhancement of Symbiotic N2-Fixation inLegumes," Annual Meeting, SouthwestConsortium on Plant Genetics, Las Cruces,New Mexico, April 17-20,1988.

Isotope and Nuclear Chemistry Division Report 19SS 101


T. R. Mills, "FOOF Production and ProcessDevelopment," FOOF'Superaeids ProjectMidyear Review, Los Alamos NationalLaboratory. April 8. 1988.

T. R. Mills, B. B. Mclnteer, and J. G. Montoya,"Sulfur and Selenium Isotope Separation byDistillation," Third International Symposium onthe Synthesis and Applications of IsotopicallyLabelled Compounds, Innsbruck, Austria,July 17-21,1988.

T. R Mills, B. B. Mclnteer, and J. G. Montoya,"Sulfer and Selenium Isotope Separation byDistillation," Third International Symposiumon the Synthesis and Applications of IsotopicallyLabeled compounds, Innsbruck, Austria,July 17-21,1988.

H. L. Nekimken, B. F. Smith, G. D. Jarvinen,and C. S. Bartholdi, "Separation of Yttrium(Y(III)) and Lanthanide (Ln(III)) Ions with the"Soft" Donor, 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazo-3-thione (BMPPT) andNeutral Adducts Using an AutomatedExtraction System," ACS Spring Meeting,Toronto, Canada, June 5-10,1988.

E. C. Niederhoffer, C. M. Naranjo, and J. A. Fee,"Iron Superoxide Dismutase and Iron Uptake inEscherichia coli," seminar(s), Department ofPharmaceutical Chemistry, University ofCalifornia, San Francisco, California, August 10,1988, and Department of Biochemistry,University of California, Berkeley, California,August 11, 1988.

E. C. Niederhoffer, "Evidence for theInvolvement of Superoxide Dismutases inthe fur Operon in Escherichia coli K-12:Is There a Physiological Role for SOD?"Occasional Seminars in Biochemistry Series,INC-4, Los Alamos, April 7,1988.

E. C. Niederhoffer, C. M. Naranjo, and J. A. Fee,"Regulation of the Iron Superoxide DismutateGene (sodB) by the fur Locus in Escherichiacoli K-12," 3rd Internationa] Conference onArchaebacteria: Genome Structure,Transcription, Translation, and GeneExpression, Vancouver Island, B. C, Canada,July 31- August 5, 1988.

E. C. Niederhoffer, C. Naranjo, and J. A. Fee,"Iron (sodB) and Manganese fsodA) Superoxide

Dismutase Regulation by the fur Locus inEscherichia coli." 1988 UCLA Colloquium onMetal Ion Homeo.stasi.s: Molecular Biology andChemistry, Frisco, Colorado, April 10-16. 1988.

D. R. Pettit, S. A. Sheffield, J. C. Dallman,R. L. Rabie, S. F. Agnew, and J. J. Dick,"Absorption Spectroscopy on Shocked N2O4,'American Physical Society General Meeting,New Orleans, Louisiana, March 21-25, 1988.

J. D. Purson, S. A. Kinkead, and J. R.FitzPatrick, "Synthesis of Krypton Difluoride,"12th International Symposium on FluorineChemistry, Santa Cruz, California, August 7-12,1988.

G. E. Oakley and R. E. Baran, "Identification ofImpurities in Enriched Nitric Oxide," AmericanChemical Society 196th National Meeting,Los Angeles. California, September 25-28,1988.

A. P. Sattelberger, "Organo-f-ElementChemistry: Balancing Theory and Experiment,"Symposium on the Interplay of Theory andExperiment in Organometallic Chemistry,March 28,1988.

A. P. Sattelberger, "Niobium and TantalumHydride Complexes," ACS Spring Meeting,Toronto, Canada, June 5-10,1988. Symposiumon the Nobel Laureate Signature Award, invited.

A. P. Sattelberger, J. C. Huffman, and W. G. VanDer Sluys, "Uranium(III) Aryloxide Complexes,"Eighteenth Rare Earth Research Conference,Lake Geneva, Wisconsin, September 12-16,1988.

B. F. Smith, G. D. Jarvinen, and C. S. Bartholdi,"Extraction Properties of Soft Donor LigandSystems," 12th Actinide SeparationsConference, Naperville, Illinois, May 8-11,1988.Invited.

B. F. Smith, G. D. Jarvinen, H. L. Nekimken,M. Jones, and C. S. Bartholdi, "Comparisonof Several Monothio-b-dicarbonyl Ligands forthe Separation of Actinide (An(IID) andLanthanide (Lndll))," ACS Spring Meeting,Toronto, Canada, June 5-10,1988.

M. A. Stroud, "The Effects of Pressure on theElectronic and Resonance Raman Specira ofQuasi-One-Dimensional Mixed Valence


Semiconductors." .seminar at Group OLS-4. LosAlamos National Laboratory, November 1.6,1987.

M. A. Stroud. B. I. Swanson, M. H. Zietlow,H. B. Gray, and H. G. Drickamer, "PressureTuning of the Electronic and ResonanceRaman Spectra of Quasi-One-DimensionalMixed Valence Semiconductors," WesternSpectroscopy Association, 35th AnnualConference on Modern Spectroscopy,Asilomar, Pacific Grove, California,January 20-22,1988.

B. I. Swanson, "Linear Chain Mixed-ValenceComplexes," Gordon Conference on VibrationalSpectroscopy, Brewster Academy, Wolfeboro,New Hampshire, August 15-19,1988. Invited.

B. I. Swanson, "Local States and PeierlsInstabilities in Quasi-One-Dimensional Mixed-Valence Solids," Department of Physics,Washington State University, Pullman,Washington, November 3,1987, andDepartment of Chemistry, StanfordUniversity, Stanford, California, November 11,1987. (Invited seminars)

B. I. Swanson, "Raman Studies of Materials atHigh Static Pressure," Xlth Inter-nationalConference on Raman Spectroscopy (ICORS),London, England, September 5-9,1988.

B. I. Swanson, "Spectroscopic Studies ofMaterials Under Exti-eme Conditions,"Picatinny Arsenal, Dover, New Jersey,January 13,1988.

B. I. Swanson, "Spectroscopic Studies ofMaterials Under Extreme Conditions,"Selected Topics in Explosive ResearchFeaturing the ISRD Program Chemistry,M Division seminar, December 9,1987.

B. I. Swanson, "Static High Pressure andShock Studies of Nitrogen Oxides,"Symposium on the Characterizationand Diagnostics of Energetic Materials,Los Angeles, California, August 9-10,1988.Invited.

B. I. Swanson and S. D. Conradson,"Spectroscopic and Structural Studies ofLow-Dimensional Mixed-Valence Solids,"International Conference on Science and

Technology of Synthetic Metals. Santa Fe,New Mexico, June 26-July 2, 1988.

B. I. Swanson, S. D. Conradson, J. Weinrach,and A. P. Sattelberger, "Structural Studiesof the Valence-Delocalized and MetastableTrapped-Valent Forms of the 1-D Mixed-ValenceSolid K4[Pt2<P2O5H2j4BrJ.nH2O," AmericanPhysical Society General Meeting, New Orleans,Lousiana, March 21-25, 1988.

C. D. Tait, J. M. Garner, A. P. Sattelberger,J. P. Collman, *nd W. H. Woodruff,"Vibrational Study of [(OEP.JM - M<OEP)]nPorphyrin Dimers," American ChemicalSociety National Meeting, Los Angeles,California, September 25-30, 1988.

S. C. Thakur and L. F. Brown, "A FrictionalFlow Model for a priori Calculation of AdsorbedPhase Transport on a Uniform Surface," 1987AIChE Annual Meeting, New York, New York,November 15-20,1987.

J. D. Thompson, M. W. McElfresh, Z. Fisk,A. C. Lawson, and A. P. Sattelberger,"Elastic Neutron Scattering in UCdll,"6th International Conference on Crystal-FieldEffects and Heavy-Fermion Physics, Frankfurt,West Germany, July 18,1988.

P. J. Unkefer, T. J. Knight, R. Dickstein, andC. Sengupta-Gopalan, "Enhancement ofSymbiotic N2-Fixation in Alfalfa and Soybeans,"4th International Symposium on MolecularGenetics of Plant-Microbe Interactions,Acapulco, Mexico, May 15-20,1988.

P. J. Unkefer: see also Langston-Unkefer.

W. G. Van Der Sluys, C. J. Burns,A. P. Sattelberger, and J. C. Huffman,"Synthesis and Characterization of U(IV)Phenoxide Complexes," American ChemicalSociety National Meeting, Los Angeles,California, September 25-30,1988.

L. S. Van Der Sluys, K. A. Kubat-Martin,G. J. Kubas, and R. R. Ryan, "Reactions ofMetal-Dihydrogen Complexes: Studies of Fe, Ru,and W," American Chemical Society NationalMeeting, Los Angeles, California, September 25-30,1988.

Isotope and Xuch'ar Clu'inistrx l)n ISIUH Rium! V.W-s 1<):1


W. G. Van Dor Sluys, R. K. Ryan, andA. P. Sattelborger, "Lanthanidc and ActinidePhosphido Complexes. Versatile Reagents inInorganic and Organic Chemistry," ACS SpringMeeting, Toronto, Canada, June 5-10, 1988.

W. G. Van Der Sluys, A. P. Sattelberger, andJ. C. Huffman, "Uranium AJkoxide Chemistry:Synthesis and Characterization of NovelAryloxide Complexes," ACS Spring Meeting,Toronto, Canada, June 5-10,1988.

W. E. Wageman, "A Simple User Upgrade toReplace the CDC CMD Disk Drives on BrukerSpectrometers," Bruker User's Group meeting,Lowell, Massachusetts, October 18-24,1987.

T. Yoshida, "A Biochemical Model of HumanErythrocytes," INC-4 Group Meeting, September9,1988.

T. Yoshida, M. Dembo, and J. A. Fee,"A Biochemical Model of Human Eryihrocytes,"American Society for Biochemistry andMolecular Biology, Las Vegas, Nevada,May 1-5,1988.

B. H. Zimmerman, C. I. Nitsche, J. A. Fee,F. Rusnak, and E. Munck, "Properties of aCopper Containing Cytochrome ba3. A SecondTerminal Oxidase from Thermus thermophilus(Tt)," American Society for Biochemistry andMolecular Biology, Las Vegas, Nevada,May 1-5,1988.

INC-5

M. M. Minor and E. B. Shera, "Real-Time DataAcquisition and Control Using Xinu in aVMEbus Environment," Symposium on Real-Time Software and Operating Systems(sponsored by the IEEE Computer Societyand the Usenix Assoc), Washington, D.C.,May 12-13,1988.

M. E. Bunker, "The Omega West Reactor asa Chemistry Resource," Chemistry ReviewCommittee, LANL, May 16,1988.

M. E. Bunker, "Review of OWR and Plans fora Replacement Reactor," LANL Managementmeeting chaired by ADR, Los Alamos, August26,1988.

INC-7

J. C. Banar, R. K. Pen-in, and R. A. Ostrengu."Multiple Filament Analyzing Turret," Thirty-Six Allied Topics, San Francisco, California,June 5-10,1988.

G. K. Bayhurst, D. L. Finnegan, R. C. Hagan,A. S. Mason, E. J. Mroz, C. L. Peach,R. Raymond, Jr., and K. H. Wohletz, MistyPicture Dust and Fallout Characterization(Draft),' MISTY PICTURE Results Symposium,Harry Diamond Laboratories, Adclphi,Maryland, December 7-10, 19S7.

B. M. Crowe, F. V. Perry, B. Turrin, S. G. Wells,and L. D. McFadden, "Volcanic HazardAssessment for Storage of High-LevelRadioactive Waste at Yucca Mountain,Nevada," Geological Society of AmericaMeeting, Las Vegas, Nevada, March 27-30,1988.

R. C. Estler, N. S. Nogar, B. L. Fearey,C. M. Miller, and M. W. Rowe, "LaserDesorption/Ablation Studies by ResonanceIonization Mass Spectrometry," ResonanceIonization Spectroscopy (RIS-88) Conference,Gaithersburg, Maryland, April 1988.

B. L. Fearey, J. E. Anderson, C. M. Miller,N. S. Nogard, and M. W. Rowe, "ResonanceIonization Mass Spectrometry of Lead andBismuth Mixtures," Resonance IonizationMass Spectroscopy (RIS-88) Conference,Gaithersburg, Maryland, April 1988.

B. L. Fearey, D. C. Parent, R. A. Keller, andC. M. Miller, "Isotopically Selective, Doppler-Free, Saturation Spectroscopy of LutetiumIsotopes Via Resonance Ionization MassSpectrometry," Resonance Ionization MassSpectroscopy (RIS-88) Conference,Gaithersburg, Man'land, April 1988.

B. L. Fearey, D. C. Parent, R. A. Keller, andC. M. Miller, "Secondary, Non-ResonantCW Laser Ionization Efficiency Enhancementfor Resonance Ionization Mass Spectrometry,"Resonance Ionization Spectroscopy(RIS-88) Conference, Gaithersburg, Maryland,April 1988.

B. L. Fearey, D. C. Parent, R. A. Keller, andC. M. Miller, "Very High Resolution SaturationSpectroscopy of Lutetium Isotopes Via CW


Appendix: Pre

Single Frequency Laser ResonanceIonization Mass Spectrometry (RIMS)," ThirdInternationa] Laser Science; Conference,Atlanta City, New Jersey, November 1-5,1987.

J. S. Gaffney, "Looking Beyond H+t Sulfatc andNitrate: Are We Missing Other ImportantSoluble and Reactive Species in Acid Rain'?."Ninth Rocky Mountain Regional AmericanChemical Society Meeting, Las Vegas, Nevada,March 27-30,1988

J. S. Gaffhey, "Organo-Nitrates in TroposphericChemistry: Missing Links?" 1988 SpringAmerican Geophysical Union Meeting,Baltimore, Maryland, May 16-20,1988.

J. S. Gaffney, J. H. Hall, N. A. Marley,G. E. Streit, and I. R. Triay, "ModelingCarbonaceous Atmospheric ChemicalProcesses," Third International Conferenceon Carbonaceous Particles in the Atmosphere,Berkeley, California, October 6-8,1987.

J. S. Gaffney, E. W. Prestbo, E. Franzblau,and C. J. Popp, "NO2 and Peroxyacetyl NitrateMeasurements in Albuquerque, New Mexico,"1988 American Chemical Society AnnualMeeting, Los Angeles, California, September 18-23,1988.

J. S. Gaffney and R. L. Tanner, "Alcohol FuelUse: Implications for Atmospheric Levels ofAldehydes, Organic Nitrates, Pans, andPeroxides. Separating Sources Using CarbonIsotopes," CRC-APRAC Methanol Fuel VehicleWorkshop, Orange, California, April 19-21,1988.

D. R. Janecky, "Coupled Sulfur Isotopic andChemical Mass Transfer Modeling: Approachand Application to Dynamic HydrothermalProcesses," 1988 American Chemical SocietyAnnual Meeting, Los Angeles, California,September 18-23,1988.

D. R. Janecky, R. S. Rundberg, M. A. Ott, andA. J. Mitchell, "Dynamic Transport of DissolvedTracers (Tritiated Water, Pertechnetate, andSulforhodamine/Thru Fractured Tuff," 1987Geological Society of America Annual Meeting,Phoenix, Arizona, October 26-29,1987.

A. Kracher, T. M. Benjamin, C. J. Duffy, andP. S. Z. Rogers, Analysis of Meteoritic Minerals

by Proton Microprobe <PIXE)," MicrobeamAnalysis Meeting. Milwaukee. Wisconsin,August 7-12,1988.

A. W. Laughlin, R. W. Charles, andD. G. Brookins, "Cenozoic Low-Silica PotassicDikes of the Navajo Volcanic Field," 1987Geological Society of America Annual Meeting,Phoenix, Arizona, October 26-29,1987.

N. A. Marley, J. S. Gaffney, Y. Minai, andG. R. Choppin, "Conformational Changes inPolyelectrolytes and the Effect on MetalBinding," 1988 American Chemical SocietyAnnual Meeting, Los Angeles, California,September 18-23,1988.

N. A. Marley, D. R. Janecky, and J. S. Gaffney,"Laser Raman and Fourier Transform Infra-RedSpectroscopic Studies of Organic Acid/SilicicAcid Complexation," 1988 Spring AmericanGeophysical Union Meeting, Baltimore,Maryland, May 16-20,1988.

N. A. Marley, P. S. Z. Rogers, T. M. Benjamin,and D. R. Janecky , "The Study of MetalSpeciation at High Temperatures and PressuresVia Laser Raman Spectroscopy," 1987 AmericanGeophysical Union Fall Meeting, San Francisco,California, December 6-11,1987.

A. S. Mason, "Long Range Atmospheric TracerExperiments in the Antarctic," Universityof Miami, Rosenstiel School of Marine andAtmospheric Science, Miami, Florida,January 15, 1988.

A. S. Mason and E. J. Mroz, "AtmosphericMethane," INCOR Meeting, Los Alamos,New Mexico, September 15-16,1988.

A. Meijer, "Evaluation of Sorption Approach,"Sorption Informational Exchange Meeting withLawrence Livermore EQ3/6 Group, Livermore,California, February 10, 1988.

A. Meijer, S. T. Kwon, and G. R. Tilton, Pb-Sr-Nd Isotopic Studies on Ultramafic Nodules,"1988 Spring American Geophysical UnionMeeting, Baltimore, Maryland, May 16-20,1988.

C. M. Miller, B. L. Fearey, B. A. Palmer, andN. S. Nogar, "High-Fidelity in Isotope RatioMeasurements by Resonance lonization MassSpectrometry," Resonance lonization Mass

Isoto/teafid Xuckar Chemistry Division Report 1HHS


Spectroscopy (RIS-88) Conference,Gaithersburg, Maryland, April 1988.

E. J. Mroz, M. Alei, and A. S. Mason, "Injectionof Deuterated Methane into the Stack of a Coal-Fired Power Plant," Air Pollution ControlAssociation Meeting, Eighty-First AnnualMeeting and Exhibition, Dallas, Texas,June 20-24,1988.

M. T. Murrell, "238U-230Th DisequilibriumMeasurements Using Solid Source MassSpectrometry," JOI Workshop on DatingMORB, Northwestern University, Evanston,Illinois, November 1987.

A. E. Norris, "Scientific Needs of the Los AlamosNational Laboratory Geochemistry Program,"U.S. DOE Workshop on Dry Drilling and CoringTechnology, Las Vegas, Nevada, July 26-27,1988.

A. E. Norris, "Diffusion Test," Yucca MountainProject Briefing for Los Alamos NationalLaboratory Deputy Directory W. F. Miller,Los Alamos, New Mexico, September 13,1988.

R. E. Perrin and M. T. Muurell, "Evaluation ofthe Boric Acid-Silica Gel System for Productionof Thermal Ions," Thirty-Sixth ASMSConference on Mass Spectrometry and AlliedTopics, San Francisco, California, June 5-10,1988.

F. V. Perry, W. S. Baldridge, and D. J. DePaolo,"Lithospheric Thinning Inferred fromGeochemical and Nd and Sr Isotopic Studies ofBasalts from the Rio Grande Rift Region," 1987Geological Society of America Annual Meeting,Phoenix, Arizona, October 26-29,1987.

E. W. Prestbo and J. S. Gaffhey, "PeroxyacetylNitrate (PAN) Measurements at a Remote Sitein New Mexico," 1988 American ChemicalSociety Annual Meeting, Los Angeles,California, September 18-23,1988.

E. W. Prestbo, W. H. Zoller, R. Dizon, J. Zieman,J. S. Gaffney, E. Franzblau, and C J. Popp,"PAN and Ozone Measurements at Remoteand Rural Oceanic and Continental InfluencedField Stations," 1987 American GeophysicalUnion Fall Meeting, San Francisco, California,December 6-11,1987.

D. J. Rokop, "Mass Spectrometry at 2.2 km,"University of Mainz, Institute of NuclearChemistry, Mainz, Germany, September 7,1988.

D. J. Rokop, "Mass Spectrometry at 2.2 km,"University of Regensburg, Regensburg,Germany, September 8,1988.

D. J. Rokop, N. C. Schroeder, and K. Wolfsberg,"High Sensitivity Technetium Analysis UtilizingNegative Thermal Ionization MassSpectrometry," Eleventh International MassSpectrometry Conference, Bordeaux, France,August 29-September 2,1988.

F. R. Roensch, R. E. Perrin, J. H. Cappis,M. Attrep, Jr., and D, W. Efurd, "Quantificationof Actinides by Isotope Dilution MassSpectrometry," South West Regional AmericanChemical Society Meeting, CosmochemistrySymposium, Little Rock, Arkansas, December 2-4,1987.

J. Rogowski, N. Kaffrell, H. Tetzlaff,N. Trautmann, D. De Frenne, K. Heyde,E. Jacobs, G. Skarnemark, J. Alstad,M. N. Harakeh, J. M. Schippers, S. Y. van derWerf, W. R. Daniels, and K Wolfsberg,"Evidence for Shape Coexistence in Neutron-Rich Rh and Ag Nuclei," International Workshopon Nuclear Structure of the Zirconium Region,Bad Honnef, Germany, April 24-28,1988.

R. L. Tanner, J. M. Roberts, J. S. Gafihey, andD. L. Sisterson, "Evaluation of SpringtimeNitrogen Oxide and Oxidant Data from aSuburban/Rural Northeast USA Surface Site,"1988 American Chemical Society AnnualMeeting, Los Angeles, California. September18-23,1988.

INC-11

FY1986

M. M. Fowler, P. Lysaght, J. B. Wilhelmy,W. B. Ingalls, and J. R. Tesmer, "AcceleratorBased Mass Spectrometry of Molecules,"American Chem. Society, Chicago, Illinois,September 8-13,1985.


dtx: I'tvst 'ft 1a tion ,s

J. A. Mercer-Smith, D. A. Cole, S. D. Figard,A. H. Herring, R. M. Lopez, D. C. Moody,P. Q. Oliver, F. H. Seurer, R. C. Staroski,F. J. Steinkruger, W. A. Taylor, andD. K. Lavallee, "Applications of MedicalRadioisotopes," invited paper, Metals inMedicine Symposium, Abstract INOR-45,American Chemical Society National Meeting,Anaheim, California, September 7-12,1986.

J. A. Mercer-Smith and D. A. Cole,"Copper-67 Research," Dimensions in Science(Radio Program #1365), Science Chroniclesand Science Log (Radio Program #223),American Chemical Society Radio Interviews.

D. J. Nichols, G. A. Izett, and C. J. Orth,"Cretaceous-Tertiary Event: vidence fromSouthern Canada," Society of EconomicPaleontologists, Raleigh, North Carolina,September 26-28,1986.

C. J. Orth, J. S. Gilmore, X.-Y. Mao, andJ. E. Barrick, "Pt-Group Element Anomaliesin the Lower Mississippian of Oklahoma," 99thAnnual Meeting of the Geological Society ofAmerica, San Antonio, Texas, November 10-13,1986.

R. D. Rieke, T. P. Burns, R. Wehmeyer, B. Kahn,"Preparation of Highly Reactive Metal Powders:Some of Their Uses in Organic andOrganometallic Chemistry," Symposium onHigh Energy Processes in OrganometallicChemistry, 192nd Meeting of the AmericanChemical Society, September 1986, Anaheim,CA, (invited paper).

F. J. Steinkruger, P. M. Wanek, A. Cui,D. R. Phillips, W. A. Taylor, and D. C. Moody,"Biomedical Generator Development at LosAlamos National Laboratory," IAEA Seminaron Radionuclide Generator Technology, Vienna,Austria, October 13-17,1986.

K. Vaziri, F. K. Wohn, D. J. Vieira, H. Wollnik,and J. M. Wouters, "Performance of theReaction-Product Transport Line Associatedwith the TOFI Spectrometer," Proc. 11th Int.Conf. on Electromagnetic Isotope Separatorsand Techniques Related to Their Application,Los Alamos, New Mexico, August 1986.

J. B. Wilhelmy, C. Albiston, J. P. Bocquet,J. Boissevain, H. C. Britt, Y. D. Chan,

R. L. Ferguson, A. Guessou.s, B. V. Jacak,P. Lysaght, G. Mamone, F. E. Obenshain,F. Plasil, C. Ristori, R. Schmidt, R. G. Stokstad,S. Wald, M. M. Fowler, A. Gavron, A. Gayer, andS. Gazes, "Saddle to Scission: Time Scales andDissipative Mechanisms," American ChemicalSociety, Chicago, Illinois, September 8-13,1985.

P. Wilde, W. B. N. Berry, M. S. Quinby-Hunt,K. Rice, C. J. Orth, J. S. Gilmore, andL. R. Quintana, "Chemostratigraphic Analysisacross a Jurassic Extinction Event in theYorkshire Toarcian," 99th Annual Meeting ofthe Geological Society of America, San Antonio,Texas, November 10-13,1986.

W. S. Wolbach, E. Anders, M. M. Grady,C. T. Pillinger, R. R. Brooks, C. J. Orth, andJ. S. Gilmore, "Carbon Isotopes and Iridium atTwo Cretaceous-Tertiary Boundary Sites inNew Zealand," 49th Meteoritical SocietyMeeting, New York, September 22-25,1986.

H. Wollnik, J. M. Wouters, and D. J. Vieira,"TOFI: An Isochronous Time-of-Flight MassSpectrometer," 2nd Int. Conf. on ChargedParticle Optics," Albuquerque, NM, May 19-23,1988.

J. M. Wouters, D. J. Vieira, H. Wollnik,G. W. Butler, R. H. Kraus, Jr., and K. Vaziri,"The Time-of-Flight Isochronous (TOFI)Spectrometer for Direct Mass Measurementsof Exotic Light Nuclei," Proc. 11th Int. Conf.on Electromagnetic Isotope Separators andTechniques Related to Their Application,Los Alamos, NM, August 1986.

FY1987

J. Boissevain, H. C. Britt, M. M. Fowler,A. Gavron, B. Jacak, P. Lysaght, G. Mamane,and J. B. Wilhelmy, "Composite ChargedParticle Detectors with Logarithmic EnergyResponse for Large Dynamic Range EnergyMeasurements," National Meeting of theAmerican Chemical Society, Denver, Colorado,April 5-10,1987.

J. S. GaRhey, J. H. Hall, N. A. Madey,G. E. Streit, and I. R. Triay, "ModelingCarbonaceous Atmospheric ChemicalProcesses," 3rd International Conference onCarbonaceous Particles in the Atmosphere,Berkeley, California, October 6-8,1987.

IsotojM! and Nuclear Chemistry Division Report 1988 U>7

Apfh'n dix: Pn-si'ii in tions

I. Gilmour, C. J. Orth, and R. R. Brooks,"Carbon at a New K-T Boundary Site in NewZealand," 50th Meeting of the MeteoriticalSociety, Newcastle, England, July 27-30,1987.

B. V. Jacak, H. C. Britt, A. I. Gavron,J. Wilhelmy, J. W. Harris, G. Claesson,K. G. R. Doss, R. Ferguson, H.-A. Gustaffson,H. Gutbrod, K.-H. Kampert, B. Kolb,F. Lefebvres, A. M. Poskanzer, H.-G. Riter,H. R. Schmidt, L. Teitelbaum, M. Tincknell,S. Weiss, and H. Wieman, "Fragmentationand Flow in Central Collisions," ACS SpringMeeting, Denver, Colorado, April 5-10,1987.

D. R. Janecky, R. S. Rundberg, M. A. Ott, andA. J. Mitchell, "Dynamic Transport of DissolvedTracers (Tritiated Water, Pertechnetate, andSulforhodamine) Thru Fractured Tuff," 1987Geological Society of America Annual Meeting,Phoenix, Arizona, October 26-29,1$87.

N. Kaffrell, J. Rogowski, H. Tetzlaff,N. Trautmann, D. DeFrenne, K. Heyde,E. Jacobs, G. Skarnemark, J. Alstad,M. N. Harakeh, J. M. Schippers, S. Y. vander Werf, W. R. Daniels, and K. Wolfsberg,"Evidence for Shape Coexistence in Neutron-Rich Rh and Ag Isotopes," Fifth InternationalConference on Nuclei Far from Stability,Rosseau Lake, Ontario, Canada, September14-19,1987.

T. D. Kunkle, F. N. App, W. L. Hawkins,A. Ogard, J. L. Thompson, W. M. Brunish,"The Aleman Radionuclide Migration Study,"The Fourth Containment Symposium, ColoradoSprings, Colorado, September 21-24,1987.

L. C. Liu, "Eta Mesons in Nuclei," Conf. onPhysics with Light Mesons, Los Alamos, NewMexico,Aug. 1987.

L. C. Liu, "Nuclear Dynamics of Bound andUnbound Eta Mesons: Eta-Mesic Nuclei andEta-Mesic Compound Nuclear Resonances,"Int. Symposium on Medium Energy Physics,Beijing, People's Republic of China, June 1987.

J. A. Mercer-Smith and F. J. Steinkruger,"Chemistry and Biochemistry ofRadiopharmaceuticals," External BiosciencesISRD Review, Los Alamos National Laboratory,Los Alamos,, November 3-5,1987.

A. E. Ogard, K. Wolfsberg, J. L. ThompsonR. S. Rundberg, P. W. Kubik, D. Elmore, andH. W. Bentley, "Migration in Alluvium ofChlorine-36 and Tritium from an UndergroundNuclear Test," International Conference onChemistry and Migration Behavior of Actinidesand Fission Products in the Geosphere, Munich,Germany, September 14-19,1987.

C. J. Orth, "Mass Extinctions of Life:A Geochemical Search for Causes," INCDivision Colloquium, October 22,1987.

R. S. Rundberg and I. R. Triay, "Modeling ofMultivalent Ion-Exchange Isotherms, NationalMeeting of the American Chemical Society,New Orleans, Louisiana, August 30-September4,1987.

R. S. Rundberg, K. Wolfsberg, D. J. Rokop,R. E. Perrin, M. T. MurrelL D. B. Curtis,G. A. Cowan, E. A. Bryant, and M. Attrep,"Mass Spectrometric Measurement of '""MoDouble Beta Decay Experiment," NationalMeeting of the American Chemical Society,New Orleans, Louisiana, August 30-September4,1987.

R. S. Rundberg, A. J. Mitchell, andB. J. Torstenfelt, "Size and Density of a 242PuColloid," Material Research Society Meeting,Boston MA, November 30 - December 5,1987.

R. R. Ryan, J. H. Hall, I. O. Bohachevsky, andI. R. Triay, "Conformation Optimization UsingGeneralized Simulated Annealing," NationalMeeting of the American Chemical Society,Denver, Colorado, April 5-10 1987.

K. Thomas, "Careers in Chemistry,"presentation and demonstration to SantaFe Indian School, October 1987.

N. Trautmann, T. Altzitzoglou, G. Herrmann,N. Kaffrell, J. Rogowski, N. Tetzlaff,G. Skarnemark, M. Skaalberg, J. Alstad,W. R. Daniels, and W. L. Talbert, "Investigationof Short-Lived Fission Products in the MassRegion a ) 110 After Fast ChemicalSeparations," 2nd International Conference onNuclear and Radiochemistry," Brighton,England.


Ap/h'n(iix: I''v'si'Titatiotin

I. R. Triay and R. S. Rundbcrg, "Deconvolutionof Ion-Exchange Isotherms," National Meetingof the American Chemical Society, Denver, CO,April 5-10,1987.

I. R. Triay and R. S. Rundberg, "Application ofthe Numerical Deconvolving Technique ofRegularization to the Analysis of Ion-ExchangeIsotherms," 36th Annual Clay MineralsConference. Socorro, New Mexico, October 18-22,1987.

A. L. Turkevich, G. A. Cowan, F. 0. Lawrence,S. D. Knight, T. Economou, W. C. Haxton," 238u Double Beta Decay Experiment;"American Chemical Society National Meeting,August 30 - September 4,1987, New Orleans,Louisiana.

D. J. Vieira, J. M. Wouters, and the TOFICollaboration, "Direct Mass Measurementsof Light Neutron-Rich Nuclei Using Fast RecoilSpectrometers,',' 5th Int. Conf. on Nuclei FarFrom Stability^ Rosseau Lake, Ontario,Canada, September 14-19,1987.

J. M. Wouters, "TOFI: Not Just AnotherCandy," Nuclear Science Division SeminarLawrence Berkeley Laboratory, May 1987.

The following four papers were presented atthe 1987 Annual Meeting of the GeologicalSociety of America, Phoenix, Arizona.October 26-29,1987:

W. B. N. Berry, M. S. Quinby-Hunt, P, Wilde,and C. J. Orth, "Use of the Cerium Anomaly inBlack Shales: Climatic Interpretation in theOrdovician-Silurian Boundary Interval, Dob'sLinn, Scotland."

K. R. Johnson, C. J. Orth, and D. J. Nichols,"Fossil Leaf and Palynomorph ChangesAssociated with an Iridium Anomaly at theCretaceous-Tertiary Boundary in North Dakota"

C. J. Orth, M. Attrep, Jr., X.-Y. Mao,E. G. Kauffman, and R. Diner, "IridiumAbundance Peaks at L^pper CenomanianStepwise Extinction Horizons."

P. Wilde, M. S. Quinby-Hunt, W. B. N. Berry,and C. J. Orth, "Southern New Brunswick -A Balto-Scandian Terranein the Tremadoc(Ordovician) Iapetus Ocean."

FY1988

M. Attrep, Jr. and C. J. Orth, RadiochemicalStudy of Biological Crisis Zones in the FossilRecord," 196th National Meeting of theAmerican Chemical Society, Los Angeles,California, September 25-30,1988.

T. P. Burns and J. A. Mercer-Smith,"Paramagnetic Contrast Imaging AgentResearch at Los Alamos Medical RadioisotopeResearch Program," INC-1.1 Seminar Series,July 28,1988.

D. A. Cole, J. A. Mercer-Smith, J. K. Norman,K. P. Williams, M. J. Behr, and D. K. Lavallee,"Localization of Water-Soluble Porphyrins inInflamed Lymph Nodes," American Society forPhotobiology 16th Annual Meeting, ColoradoSprings, Colorado, March 13-17,1988.

D. A. Cole, J. A. Mercer-Smith, K. P. Bullingtcn,J. K. Norman, M. J. Behr, and D. K. Lavallee,"The Uptake of a Copper-67 Labeled Porphyrinby Inflamed Lymphatic and NonlymphaticTissues," Federation of American Societies forExperimental Biology (FASEB), 72nd AnnualMeeting, Las Vegas, Nevada, May 1-5,1988.

M. M. Fowler, "The Development of thePAGODA Detector System and SomePreliminary Results from Nb + Au at 100Mev/Nucleon," Univ. of Mainz, April 7,1988.

B. M. French, C. J. Orth, and L. R. Quintana,"Iridium in Vredefort Bronzite Granophyre:Impact Melting and Limits on a PossibleExtraterrestrial Component," 19th Lunar andPlanetary Science Conference, Houston, Texas,March 14-18,1988.

T>. K. Lavallee, J. A. Mercer-Smith, D, Ai Cole,J. C. Roberts, and R. Fawwaz, "Gamma Imagingwith Metalloporphyrins," Abstract INOR-13,Metalloporphyrin Symposium, 196th AmericanChemical Society National Meeting, LosAngeles, CA, September 25-30,1988.

D. K. Lavallee, J. A. Mercer-Smith,J. C. Roberts, D. A. Cole, and R. A. Fawwaz,"Novel Porphyrins: Stable Chelators forImaging Applications," Florida Conferenceon Chemistry in Biotechnology, 1988:Biomedica) Applications of Metals, PalmCoast, Florida, April 26-29,1988.

Isotope and Nuclear Chemistry Division Report 1988 JG9


C. J. Orth and M. Attrep, Jr., "ElementalAbundance Patterns Across Bio-EventHorizons," Spring Meeting of the AmericanGeophysical Union, Baltimore, Maryland,May 16-20,1988.

C. J. Orth and M. Attrep, Jr., "IridiumAnomalies and Mass Extinctions~A Searchfor Periodicity," Albuquerque GeologicalSociety, September 20,1988.

C. J. Orth, M. Attrep, Jr., L. R. Quintana,R. Diner, and W. P. Elder, "SiderophileAbundance Maxima at Upper CenomanianMarine Invertebrate Extinction Horizon:Western Interior of North America,"19th Lunar and Planetary ScienceConference, Houston, Texas, March14-18,1988.

P. D. Palmer, "Preparation and Characterizationof Pure Oxidation States of the ActinideElements," presented to the Central New MexicoSection of the Technicians Affiliate Associationof the ACS at Sandia National Laboratories,March 10,1988.

J. C. Roberts, J. A. Mercer-Smith,S. A. Schreyer, D. A. Cole, S. D. Figard,and D. K. Lavallee, "Labeling Proteins withCopper-67," Florida Conference on Chemistryin Biotechnology, 1988: Biomedical Applicationsof Metals, Palm Coast, Florida, April 26-29,1988.

J. Roberts, J. Mercer-Smith, D. Cole,S. Schreyer, S. Figard, and D. Lavallee, "Site-

Directed Imaging and Therapy of Cancer UsingCopper-67 Labeled Monoclonal Antibodies,"Third Santa Fe Graduate Medicinal ChemistryConference, Santa Fe, New Mexico, August 7-9,1988.

J. C. Roberts, S. A. Schreyer, D. A. Cole,J. A. Mercer-Smith, S. D. Figard, andD. K. Lavallee, "Porphyrins as ChelatingAgents for Labeling Antibodies with CopperRadioisotopes," Metalloporphyrin Symposium,196th American Chemical Society NationalMeeting, Los Angeles, California, September25-30,1988.

J. C. Roberts, H. T. Nagasawa, J. A. Elberling,and E. G. DeMaster, "Prodrugs of D-Penicillamine in the Sequestration of Ethanol-

Derived Acetaldehyde," 21st National MedicinalChemistry Symposium, Minneapolis, Minnesota,June 16-23,1988.

F. J. Steinkruger, "New Generators forDiagnostic and Therapeutic Nuclides," 35thSociety of Nuclear Medicine Annual Meeting,San Francisco, Calif., June 14-17,1988.(Continuing Education Course -Radiopharmaceuticals from Parent/DaughterGenerator Systems). •;

K. Thomas, "High School Requirements for anAdvanced Technical Degree," MathematicsInstitute for Teacher Enhancement, Los AlamosNational Laboratory, June 17,1988.

K. Thomas, 'Chemistry is Fun," presentationand demonstration to Pinon Elementary School-1/88, Kachina Preschool-4/88, and the YMCAAfterschool Program-4/88.

Thompson, J. L., "The Los Alamos Program,"Hydrology/Radionuclide Migration ProgramSteering Committee Meeting, Las Vegas,Nevada, September 15-16,1988.


Division Meetings and Seminars

Advisory Committee for Isotope and NuclearChemistry Division, July 19-22,1988

Afi/M'ii(f(x: Oil in/t/tt Xh'fttni's rind Sr

Donald W. Barr, "Response to 1987 CommitteeReport and Summary of Division Activities"

Robert Ryan, "Isotope and Structural ChemistryOverview, INC-4"

Merle Bunker, "Research Reactor Overview,INC-5"

Bruce Crowe, "Isotope Geochemistry Overview,INC-7"

William Daniels, "Nuclear and RadiochemistryOverview, INC-11"

Robert Charles, "Sleuthing the Geochemistry atSalton Sea"

Michael Murrell, "238(j.230jn DisequilibriumMeasurements Using Solid Source MassSpectrometry"

Jeff Gaffney, "Tropospheric Chemistry of Organics"

Nancy Marley, "Laser Raman Investigations ofAqueous Geochemical Complexation"

Merle Bunker, "Low-Energy Nuclear StructureResearch"

Michael Minor, "The Integrated Omega WestReactor (OWR) Laboratory"

James Fee, "The Stable Isotope Resource andan Overview of the Biochemistry Section of GroupINC-4"

Michael Mather, "Cloning Cytochrome OxidaseGenes from Thermus"

Clifford Unkefer, "Biosynthesis of the CoenzymePQQ in Methylobacterium AM1"

Pat Unkefer, "New Insights into the Control ofSymbiotic N2-Fixation"

Gordon Jarvinen, "New Directions in ActinideSeparation Chemistry"

Inez Triay and Robert Rundberg, "Developmentof an Innovative Technique for the Study of CationExchange in Synthetic and Natural Exchangers"

David Hobart and David Morris, "The Chemistryof Actinides Under Environmental Conditions"

Moses Attrep and Wes Efurd, "Requirements,Techniques and Capabilities for Low Abundance,High Purity Radiochemical Determination"

Phil Chamberlin, "Electromagnetic IsotopeSeparation: Progress and Plans"

Isotope and Xucltar Chi'rm-:tr\ ])nis;i>n Annual R<]»>rt FY 111

Appendix: Division Meetings and Seminars

Division Seminars

"Immunization with Rat Osteosarcoma CellsYield Monoclonal Antibodies that RecognizeTwo Distinct Cell-Associated Proteoglycans,"Jeffrey P. Gorski. University of Missouri, October29, 1987.

"Mass Extinctions of Life: A Geochemical Searchfor Causes," C. J. Orth, INC-11, October 22, 1987.

"Seismosauras of San Ysidro," Steve Agnew,INC-4, November 19, 1987.

"Technetium Chemistry and Its Relevance toNuclear Medicine," Alan Davison, Department ofChemistry, Massachusetts institute of Technology,December 3, 1987.

"Coordination of Hydrogen Molecules to MetalCenters: Prototype for Nonclassical ChemicalBonding," Gregory J. Kubas, INC-4, January 21,1988.

"Accelerator 14C Dating of Amino Acids:Applications in Quaternary Geology andPaleontology," T. W. Stafford, University ofNew Mexico, March 11, 1988.

"Recent Development in X-Ray AbsorptionSpectroscopy at Los Alamos," Steven Conradson,INC-4, April 21, 1988.

"Humics and Radionuclide Migration," Gregory R.Choppin, Florida State University, April 22,1988.

"A Fortran Precompiler and System forAutomating the Implementation of Forwardand Adjoint Deterministic Sensitivity Methodsinto Existing Fortran Computer Codes,"Brian A. Worley, Oak Ridge National Laboratory,April 27, 1988.

"Stripa Project," Edward S. Patera, US Departmentof Energy, Argonne, Illinois, July 6,1988.

"Kinetics of Crystal Growth in Igneous Systems:Experiments and a Simple Model," Gregory E.Muncill, Carnegie Institution of Washington, July26, 1988.

"The Speciation of Transuranic Ions in NaturalAquifer Systems by Laser Induced PhotoacousticSpectroscopy (LPAS)," Professor Jae-il Kim,University of Munchen, September 9, 1988.

112 Isotope and Nuclear Chemistry Division Report FY 1988

Appendix:

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2. Jacob Kleinberg and Merlyn E. Holmes,Comps. and Eds., "Collected Radiochemicaland Geochemical Procedures, 5th Edition,"Los Alamos National Laboratory reportLA-1721, 5th ed. (July 1989).

3. E. P. Chamberlin, K. N. Leung, S. Walthers,R. A. Bibeau, R. L. Stice, G. M. Kelley, andJ. Wilson, Nucl. lustrum. Meth. Phys. Res.B26, 227 (1987).

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8. D. R. Houck, J.L. Banners, and C. J.Unkefer, J. Am. Chem. Soc. 110, 6920-6921(1988).

9. D. R. Houck, J.L. Hanners, C.J. Unkefer,M. A. G. van Kleef, and J.A. Duine, "PQQ:Biosynthetic Studies in MethylobacteriumAMI and Hyphomicrobium X UsingSpecific l^C Labeling and NMR," inProceedings of the 1st InternationalSymposium on PQQ and Quinoproteins(1989, in press).

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15. Phillips et al., Appl, Radial. IsoL 38, No. 1,521-525, (1987).

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18. W. Alvarez and R. A. Muller, Nature 308,718 (1984).

19. D. M. Raup and J. J. Sepkoski, Jr., Proc.Natl. Acad. Sci. 81, 801 (1984).

20. C . J. Orth, M. Attrep, Jr., X.-Y. Mao, E. G.Kauffman, R. Diner, and W. P. Elder,Geophys. Res. Lett. 15, 346 (1988).

21. B. M. Crowe, D. L. Finnegan, W. H. Zoller,and W. V. Boynton, J. Geophys. Res. 92,B13,13708-13714 (1987).

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26. D. E. Hobart, D. E. Morris, and P. D.Palmer, "Formation, Characterization, andStability of Plutomum(IV) Colloid," LosAlamos National Laboratory documentLA-UR-87-3505 (1987).

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114 Isotope and Nuclear Chemistry Division Annual Report FY I9HH

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