POSTER SESSION.Nl -HIGH RESOLUTION FOURIER TRANSFORM UV EMISSION SPEC-TROSCOPY OF THE 410 NM BAND OF THE TiCl RADICAL

TAKASHI IMAJO, DONGBING WANG, KEIICHI TANAKA,AND TAKEHIKO TANAKA, Department 01 Chemistry, Faculty 01Science, Kyushu Umversity 33,Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan; ,.

High resolution UV emission spectrum of the 410 nm band of the TiCl radical wasmeasured by Fourier transform spectrometer (Bruker IFSI20HR) with a rcsolution of0.04 cm-1. This band was assigned as the electronic transition 2cþ_2 ð. of the TiCI radi-cal by Phil1ips and Davis [11,but a recent study of ZrCl [2)suggested that this band mightbe the 4r - x4cþ or 4CÞ- X4CÞband.In the present work a new electronic assignment of4r'- x4cþ is proposed. Thc vibrationalassignments wcre made for each sl1bbands. The vibrational bands of (0-0), (1-1), (2-2),(3-3), and (4-4) were assigl1ed for the subbands 4r~/2 _4 CÞ3/2and1r7/2 _4 CÞ~/2'Forthe subband 4r9/2 _4 CÞ7/2'the (0-0), (1-1) and (2-2) bands were as.~igned,but for the

4r \Jj2 - 4CÞ~2subband, only the (0-0) band was assigned. Rotational analyscs were donefor r 5/2 - CÞ3/2 and 4 r 7/2 - 4 CÞ~/2 subbands. The band origins, rotational constants,

and centrifugal distortion constants were determined by thc least squares method. Therotational constants for the lower states were consistcnt with thosc of X .1cþ reportedby Ram and Bernath [3] within the expcrimental error. From the 1inc intensities of p-and R- branches. ð.f! was dcrivcd to bc + 1. Furthcr measuremcnts and analysis for the

sl1bbands 4r9/2 _4 CÞ7/2and 4rll/2 _4 CÞ9/2arel1eeded to cOl1firmthe presel1t electronicassignment definitely.

1. J. G. Phillipsand S. P. Oavis, Astrophys. J. Suppl. Ser 71, 163-172(1989).2. R. S. Ram and P. F. Bernath, J. Mol. Spectrosc. 186,335-348 (1997).3. R. S. Ram and P. F. Bcrnath, J. Mol. Spectrosc. 186. 113-130(1997).

r

POSTER SESSION, N2-JIIlVESTIGATING THE APPLICATIONS OF A COMMERCIAL FTIRINSTRUMENT WITH TIME RESOLVED CAPABILITIES TO STU-DIES OF CHEMICAL KINETICS IN A MODULATED HOLLOW CA-THODE DISCHARGE PLASMA REACTOR

T. DE LOS ARCOS, C. DOMINGO, V. J. HERRERO,I. TANARRO, lnstituto de Estructura de la Materia, CSIC, Serrono123, 28006 Madrid, Spain; M.M. SANZ, Departamento de Física Apli-cada, Universidad Alfonso X el Sabio, 28691 Villanueva de la Cañada,Madrid, Spain.

r

,

Time-resolved FTIR spectroscopy is proving to be a very adequate tool for studying time-

evolving phenomena. Most of the time-resolved FTIR experiments previously done in gas

phase dea1 with laser excitation of the sample used as precursor, mainly for the productionof transient species to be studied spectroscopica1ly. The available commercial FTIR ÍD8tru-mcnts, with rapid and step-scan possibilities for doing time-resolved studies, are prepared

for such kind of molecular excitation, where the "duty cycle" is less than 1 %. Never-theless, therc is a very interesting lield related to characterization and modelling of "cold

plasmas" produced in square-wave modulated electrica1 discharges where the "duty cycle"is 50 %. Wc have investigated and evaluated difl'crent ways of extracting useful informa-tion from transmittance (and emission) spectra of modulated discharges, in the range oftenths to ten5 of Hz, in order to get non steady-state data of the molecular spedes present

in cold plasmas produced in hollow cathode discharges of N20. The time resolved data

havc provcd to be specially relevant for testing and improving our recently reported ki-netic model of thc discharge 1, which was stablished taking into account only steady-statedata. On the other hand, a phase dctection method has been applied to emiasion and

ab50rption mcasurements of the modulated discharge. With this detection method theblackbody radiation is removed from the emission spectra, while in the absorption exper-imcnts it is possible to observe the spectra of the products, which have opposite phase

to that of thc prccursor. Furthermore, a double modulation method (internal or "phase"modulation, and modulation of thc discharge) similar to one of the previously proposed 'by

IlS for high re501lltion infrared laser spectroscopy 2, is under study. AII measurements havebeen madc with a Brukcr IFS66, with rapid and step-scan possibilities, spectral resolutionIIp to 0.1 crn-1 and timc rcsolution up to 5Jjs. The difl'erent approaches are dÎ!<cussed.

This work was partially supported by thc European Commission (Project ENV4950011)

ancl by Spanish DGICYT (Projcct PB96-0881).

I T. de 105Arcos, C. Domingo, V. J. Hcrrero, M. M. Sanz, A. Schulz and 1. Tanarro, "Diagn06ticand kinetic modeling of a hollow cathode N20 discharge", J. Phys. Chem., in press (July 1998).

2 C. Domingo, 1. Tanarro, M. M. Sanz, J. Santos, D. Bermejo and C. Aroca, "New very SCDSitivcdOllble modulation techniques for the detection of high resolution infrared absorption spectra of

radicals, molecular ions and excited states of stable molecules", Laser Techniques for State-Selectedand State to State Chemistry, J.W. Hcpbum, Ed. SPIE 2124, 227-232, (1994).

POSTER SESSION, N3

VIBRATIONAL SPECTROSCOPY OF VA GROUP VOLATILEHYDRIDES IN LIQUID PHASE

SH. SH. NABIEV, P. G. SENNIKOV,I.I.OSTROUKHOVA, L.A.PALKINA,E.V.YASHINA, Russian Research Center123182 Moscow, Russia.

B. G. SARTAKOV,N.V.REVINA AND

"Kurchatov Institute",

The investigation of processes with the VA group 2, 3 and 4 periods volatile hydrides

in the gas and liquid phases (for example, the process of epitaxial semiconductive A3Bsstructures synthesis) requires the knowledge of the series of physical-chemical properties

of these compounds, which are caused by the character of the X-H bonds (X = N,P,As),specificity of their vibrations, structural peculiarities and dynamic parameters in the case

of the strong intermolecular interactions. Howewer, the existing information concerningthe structural and molecular parameters of the most known volatile hydrides in the liquidphase is fragmentary and contradictory, and the information on the dinamic parametersis absent practically.The present paper is devoted to the detailed investigation of vibrational spectra and

analysis of the spectral band contours of the high-purity ammonia, phosphine and an;inein the liquid phase. To obtain the spectroscopic information concerning the VA group

hydrides in the wide temperature region (298-150 K) the Raman and IR-cryospectroscopywere used. An analysis of the vibrational spectra of the liquid hydrides in the region

2500-700 cm-I has shown that in the whole temperature range thc VI and v3 stretchingbands overlap completely. On the basis oC experementally obtained halC-width values oCthe 1'2 and V4 bending bands in the m spectra oC PH3 and AsH3 in the liquid phase

(T=153 K) and liquefied Ar solution (T=98 K), the angular moment correlation times

(Trot = 0.1 and 0.2 ps, accordingly) were obtained. The estimates carried out for theintermolecular intcraction entalpy in the liquid hydrides showed that thcir values dilferconsiderably: -1.7 kcal/mole (NH3), -0.1 kcal/mole (PH3) and virtually zero (AsH3). Onthe basis of the I'2(Ad band contours with the frequcncies 980 cm-1 (PH3) and 900 cm-I

(AsH3) in Raman spectra, the correlation Cunctions oC vibrational (G\.(t.)) and rotational(GR(t)) relaxation wcrc calculatcd. An analysis oC thc Gv(t) and GR(t) timc depcndenccand values oC vibrational (TI') and rotational (TR) relaxation timcs showed that the T\'

slightly depends on the tempcrature oC PH3 and AsH3 (1.2-1.5 ps). In contrast to T\',

the temperature Call of liquid hydrides in thc region 298-181 K Collowed by the essentialgrowth oC TR: from 3.1 up to 7.4 ps (PH3) and Crom 0.4 up to 4.8 ps (AsH3). Thc main

mcchanisms oC the I'2(A1) line contour Cormation in Ramau spcctra oC thc liquid hydridesarc discussed.

The spectroscopic and dynamical data obtained Cor the liquid NH3. PH3 and AsH3 in thc

wide temperaturc region allow to make the following conclusiollS. Among the VA grouphydrides the NH3 has thc highest tendency to selfassociation by means oC H-bonding. Incase of PH3 the specific interactiollS Collowed by H-bonding selfassociates are weaker thanfor ammonia. In contrast to the NH3 and PH3, in the liquid AsH3 thc nOllSpecific van der

Waals interactions predominatc at low temperature.The research described in this talk was made possible in part by Grant No. 96-03-34250from the Russian Foundation Cor Fundamental Research.

r POSTER SESSION, N4

SPECTROSCOPIC AND ELECTROOPTICAL EXHIBITIONS OFINTERNAL ROTATIONS WITHIN COMPLEX L[MX3] MOLECULES

L. P. SUKHANOV, Russian Research Center "Kurchatov Institute",123182 Moscow, Russia.

On the basis of the electron diffraction data and ab initio ca1culations of the potentialenergy surfaces (PES's), it was shown (see, e.g.,1) that the complex molecules of theL[MX3] type (L = alkali metal, M = element of IIA and VA group, X = H,F,O) arenonrigid systems with respect to the L+ cation migration in the plane of the triangularanion [MX3t. The large amplitude motioD8 (LAM) within the compounds of such atype are able to be exhibited in an unusual character of their vibrational spectra andelectrooptica1 properties including the dipole moment behaviour. Unlike the traditionalviews on the mechanics and electrooptics of vibratioD8 and the geometry of polyatomicmolecules, the study of the structural non-rigidity eft'ects requires the use of the originaltheoretica1 approaches for the vibrational molecular spectroscopy.In the present talk, the spectroscopic and electrooptica1 exhibitions of the LAM withincomplex L(MX3] molecules are investigated using the earlier ca1cu1atedPES's and dipolemoment functions. The original code2 of the fìnite element method was deve10ped byus for the description of vibrational spe.ctra of the LAM along the PES's of the veryarbitrary form. For the studied molecules, the tunneling splittings (> 10-5 cm-1) ofenergy levels with the LAM number n which are observable for the microwave vibrationalspectroscopy appear only starting with nO= 10, 12, 13 and 32 for NaBeH3, LiBeH3, LiP03and LiBeF3, respectively. The internal rotations in these molecules are exhibited in a sharpdiminution of their polarity starting with lower ñ = 8, 10, 9 and 29, respectively.80ththe spectroscopic and electrooptica1 efl'ects of the structural non-rigidity become strongerin the row of molecules L(MF3] - L[MH3].For the experimentalstudy of the anomalousdipole moment behaviour, the selective multiphoton population of vibrationalstates withthe indicated numbers ñ is necessary. The temperature dependences of the structuralparameters and dipole moments of the L(MX3] molecules are investigated using the dataof our ab initio dynamical calculations.The rcscarch described in this talk was made possible in part by Grant No. 96-03-34250from the Russian Foundation for Fundamental Research.

1. O. P. Charkill and A. I. ßoldyrev, Potential energy surJaces and strnctural non-rigidityoJ inorganic mo/ecu/es. Advances ill sciellce and technology. Series "Inorganic Chem-istry", Vo1.8.VINITI, Moscow (1980).2. V. V. Gusev, S. G. Potapov and L. P. Sukhanov, Sov. J. Theor. Exp. Chem., 27, 442(1991).

POSTER SESSION,N5

TIME-REVERSAL OPERATION APPLIED ON AN ALGEBRAICHAMILTONIAN ADAPTED TO TETRAHEDRAL MOLECULES

C. LEROY, V. BOUJUT, F. MICHELOT AND H.-R. JAUSLIN,Laboratoire de Physique de /'Université de Bourgogne-CNRS, B.P. 400,F-21011 Dijon, rmnce.

Wc analyse thc implcmentation of the time-reversal (TR) transformation in thealgebraic approach to tetrabedral local molecules through the chain of groupsU(5) :) U(4) :) K(4) = A(4) ^5(4) :) 5(4) :::: Td. We determine the gcn-eral form of the TR operation using a purely algebraic realization, based exclusive1y onthe requirement that the irreducible representations must not be changed under the timeinversion symmetry. As a result we can detennine the J'R behavior of all the quantitiesinvolved in our formalism, not only the generators of the dynamical group U(5), but alsoof the Boson operators. We show that the transformation laws depend on two parametersw and w" which may be fixed by the physical interpretation of each particular model.Moreover, not only for the Hamiltonian but the matrix elements of any operatorG builtthrough this formalism do not depend on the parameters w and w".

GC. LEROY,V. BOUJUT,J. Mol. Spedro!c. 181,127-135 (1997)

POSTER SESSION, N6-J(_DEPENDENCE OF BROADENING COEFFICIENTS FOR THEsYSTEM CH3F-N2.

MURIEL LEPÈRE,GHISLAIN BLANQUET,JACQUES WALRAND,Laboratoirede SpectroscopleMoléculaire, Facultés Universitaires Notre-Dame de la Paix, 61. rue de Bruxelles, B-5000 Namur, Belgium;JEAN-PIERRE BOUANICH, Laboratoire de Physique Moléculaireet Applicatwns, CNRS, Université de Paris-Sud, Bâtiment 350, F-91405Orsay cedex, France.

In ordcr to study the variations of colIisional broadening coeflìcients 1'0 with the rotational

C(uantußI nUIIlI)('r K. we have rccordcd about 15 lines of CH3F in the 1'2and 115bands, usinga tllllab\e diode-\a..,er speetrometero. The lines have been associated in family with same

I'rindpa\ rotationa\ qnantum number J, and with same AJ and AK. We have studied 4different familics (J comprised between 3 and 17) in the spectra\ range 1478-1573 cm-1,cach family induding 3 or 4 different va\ues of K. To determine the col1isional widths, we

have fittcd Voigt and Rautian profi\es to the measured shapes of the lines. A comparisonis made with rcsults obtaincd by ca\cu\ations based on a semi-c\assica\ impact mode\ in

which the intcrmo\ecu\ar potentia\ inc\udes electrostatic, induction and dispersion energy

Wllt ributiolls. An ovcral1 agrcement is obtained between the predictions of the theory andthe eXl'erimental rl'slllts.

"M. Lcl'èrl'. G ßlanqllct. J.Wa\rand. and J.P. ßouanich. J. Mo\. Spectrosc. 180, 218-226(1996).

POSTER SESSION.N7

ISOTOPIC SUBSTITUTION IN THE NEAR LOCALMOLECULES: HIGH RESOLUTION STUDY OF THE 111

BANDS OF D2Se

MODEand 113

O.N. ULENIKOV, E.A. DITENBERG, AND G.A. ONOPENKO,Laboratory 0/ Molecular Spectroscopy. Tomsk State University. 634050,Tomsk, Russia; H. BÜRGER, W. JERZEMBECK, Anorganis-che Chemie, FB9, Universitãt-Gesamthochschule, D-42097 Wuppertal,Gen1lany.

The high resolution (0.0027 cm-I) Fourier transform spectrum of thc D2Se molccule as 80Semonoisotopic and natural material was recordcd for the first time in the 1500 1900 cm-I

region where the 111and V:I vibration-rotation bands are located . Because accurate infor-mation about thc rotational structures of both the ground and of the uppcr vibrational

states is stilllacking the analysis was begun with the construction of a synthetic spectrumfor the 111and V:Ibands. To rcalize such a proccdure, the earlier derivcdG "expandcd loca1

mode" model was used for the construction of isotopic relations between spectroscopic

parameters oC the XH2 molecule (in our case H2Se) and the corresponding values oC itsisotopic species XD2 (D2Se in our case). Simple isotopic relations were obtaincd between

relatcd pairs oC spectroscopic parameters, which were then used to generate a syntheticspectrum.

By this proccdurc, a) lines oC the recorded spectrum wcre assigned, and b) balld centers,

rotational, centriCuga1 distortion, and resonance interaction paramctcrs of thc (000), (100),and (001) states for the species MSeD2, M = 76, 77, 78, 80, and 82, were dctermincd withthe help oCthc cOlllbination differences method. The obtaincd sets of parameters reproduce

both the initially uscd "mean" values oCground state combination differenccs, and valucs

of uppcr statc rotation-vibration encrgies. with an accuracy oC 0.00006-0.00008 cm-I ingeneral.The results are discusscd with regard to "Iocal mode behavior" of the ScD2 molecule in the

ana1yzcd states. The cOlllparison oC thc experimental\y detcrmined spcctroscopic param-

cters and the prcdictions employing the derivcd isotopic relations shows high correlation.

.O.N. ULENIKOV, R.N. TOLCHENOVAND Q.-S. ZHU. Spectrochim. Acta. A52, 1829 1841(1996)

-- POSTER SESSION,N8

rØE B-TYPE MICROWAVE SPECTRUM OF PHENOL-WATER:VIPOLE MOMENT AND BARRIER TO INTERNAL ROTATION

llANIELA CONSALVO, Institut [ür Physikalische Chemie, RWTH:\.achen, Templergraben 59, 52056 Aachen, Germany; MICHAELSCHMITT, Institut [ür Physikalische Chemie 1, Heinrich-Heine-U/Jiversität,40225 Düsseldorf, Germany,

Fourier transform microwave spectroscopy in a molecular beam is not a mass selectivetechniquc. thcrcforc while searching for complexes one bas to care for all species presentin the bcam, from thc monomcrs to large molecular complexes. While searching for the

phenol-dimcr complex we reanalyzed the spectrum of phenol-water, found evidence forIrtype trallsitiolls alld measured the b-type spectrum. .This system was previously studied and thought to have a pure a-type asymmetric rotor

spectrum, split by illternal rotation of the water moiety o.The electric dipole moment measurements, now possible at the RWTH- Aachen b, show

that J1bis largcr than 1 Debye.

The gained information provides new insight on the structure of the complex and its

d)'uamics. Fitlillg thc a=O alld a=1 transitions allows to determine the barrier to intemalrotatioll of the water moleculc, and to predict the ð.a=1 transitions.

8M. Gcrhards, M. Schmitt, K. Kleinermanns, and W. Stahl, J. Chem. Phys. 104 (1996) 967.bD. Consalvo. Rev. Sci. Instrum. submitted for publication.

POSTER SESSION,N9

HIGH-RESOLUTION STUDY OF THE D3Si35Cl INFRARED SPEC.TRUM IN THE 440-590 AND 900-1100 CM-1 REGIONS; ACCURATEDETERMINATION OF THE GROUND STATE CONSTANTS, IN.CLUDING Ao AND D~

A. CEAUSU, G. GRANER, Laboratoirede Physique Moléculaire etApplications, CNRS, Bât. 350, Campus d'Orsay, F-91405 Orsay Cédex,France;E.B. MKADMI, ANDH. BÜRGER, Anorganische Chemie,FB 9, Universität-Gesamthochschule, D-42097 Wuppertal, Germany;P. PRACNA, J. HeyrovskýInstitute 01PhysiclIlChemistry, Dolejskova3, CZ-18223 Prague, Czech Republtc.

In a previous study. of monoisotopic D3Si35CI; the analysis of the fundamental bandsV3 and V6, linked by a Coriolis resonance, was reported. Ncw Fourier transform infrarcdspectra of this compound were recorded in the 440-590 cm-I and 900-1100 cm-I regions.in order to obtain accurate rotational ground state constants.

In the fìrst spectral region, the rovibrational study of thc VJ and V6 fundamcntal bands.has now bcen cxtended, and the available data (3753 non-zero weighted transitions) werefìtted using two diffcrent reductions of the effective Hamiltonianb. Thc 2v;2_v;I, 2vg-v:1and (V3+v;I)-v;1 hot bands have also been assigned and analyzed. Thc (v3+vf1)-v;1band served to obtain accurate energics of the (V3=V6=1) Icvel, thc V3+V6combinationband being too wcak to bc dctccted on our spcctra.

In the second spectral region, a detailed rovibrational study was donc for thc 2vg, 2v[1and 2V3 ovcrtonc bands. Their experimenta1 wavenumbers, togethcr with 59 energiesof the (v3=v6=1) level, wcre fìtted to a moclelwhich accounted for thc Coriolis-typcrcsonanccs bctwccn the IIpper levels of thesc bands.

The fìrst experimenta1 dctermination of the Ao and D~. rotational r.onstants was IIn-dertaken by thc now well-cstablished method, using the V6, 2v:2 and 211;2-v;1 bands.Ground state differenccs llK(J)=Eo(J, K)-Eo(J, K - 3) were calclllated for K valucs from2 to 16. By a least-squares fìt of 339 such differenccs, with a s.d. of 0.394 x \0-3 cm-I,the Ao and D~ thus obtained were (in crn-1): Ao =1.4278332(8) and D~=5.3870(33)x\0-6.

"J.E. Gadhi, H. Bürger, and E.B. Mkadmi, J. Mol. Speclrosc., in press.6E.L Lobodcnko, O. N. Sulakshina, V. L Perevalov, and VI. G. Tyutcrev, J. Mol. Speclrosc.

126,159-170 (1987).

POSTER SESSION, NIO--rHEV2 BANDS OF THE DEUTERATED SPECIES D2Se AND HDSe

J.-M. FLAUD, Laboratoire de Photophysique Moléculaire, CNRS,Bât. 210. Université Paris-Sud, F-91405 Orsay Cedex, l'rance; P.ARCAS, Laboratoire de Physique Moléculaire et Applications, CNRS,Bât. 350, Université Paris-Sud, F-91405 Orsay Cedex, l'rance;W. JERZEMBECK AND H. BÜRGER, Anor:qanischeChemie,FB9,Ber:qischeUniversität - Gesamthochschule Wuppertal, D-42097 Wupper-tal, Germany.

For the first time D2Se and HDSe as 80Se monoisotopic and natura1 materia1 have been

studied in the region of the v:l fundamenta1 vibration by high resolution (0.0033 cm-1)Fourier transform infrarOO spectroscopy. For D2Se which is an asymmetric rotor with C2v

symmetry the v:l band is of B-type while for HDSe with C. symmetry it is a hybrid band,and both A- and B-type transitions have been observed. Ground state combination dift'er-

ences and (010) excitOO state energies have been 6ttOO using a Watson-type Hamiltonianin A reduction and yr representation. Depending on the isotopic abundance ca. 500 to

1000 liues have been fittOO for each of the isotopic MSe species, M = 76, 77, 78, 80, and

82, and rms deviations for the ground and excitOO state data were of the order of 1.5 - 3 X10-4 cm-1. For the 80Se isotopic species the band centers are: HDSe 900.43841(3) cm-1,D2Se 741.67499(3) cm-I. Hamiltonian constants up to high order (sextic and octic) have

been derivOO with high significance.

POSTER SESSION,Nll --MICROSCOPIC APPROACH TO THE DESCRlPTION OF MOLECU.LAR ROTATION: CRlTICAL PHENOMENA IN THE ROTATIONALDYNAMICS OF HDX-TYPE NONSYMMETRlCAL HYDRlDES (X::::0, S, Se, Te, ...)

SERGEIV. PETROV, SERGEI E. LOKSHTANOV,Moscow State University, Department 01Chemistry.Moscow 119899, Russia.

Theoretical method allowing to analize rotational dynamics of molecules in case of strongro-vibrational interaction is presented. Our method is based on the stability analysis of ef.fective rotational Hamilton function stationary points. This function is obtained from totalclassical rovibrational Hamilton function by its minimizing with respect to vibrational co-ordinates and conjugated momenta. Ab50lute value J of total angular momentum vector j

being integral of motion, effective rotational Hamilton function may be considered as the

function of j vector direction assuming J value fixed. This function represents 50 calledRotational Energy Surface (RES) and stability analysis of stationary points mentionedabove can be carried out as bifurcation analysis of RES.

The results of such an approach as applied 10 the rotational dynamics of HDX-type non-

symmetrical hydrides are presented. The symmetry breaking from C2u down to C. point

symmetry aIlows 50 called imperfect bifurcation of RES to occur. Corresponding criticalvalues of total angular momentum are found as functions of molecular parameters.

POSTER SESSION, N12

ABSOLUTE INTENSITY MEASUREMENTS FOR 002 IN THE 1.74JJREGION

F.. J. KSHIRSAGAR,L. P. GIVERANDC. CHACKERIAN,JR,NASA Ames Rese4rch Center, Moffett Field, Califomia 94035-1000.

Tbe emission spectra1 window in Venus' night-side spectrum at 1.74 p is defined by the(00031-10002)band of 12C1602at 5687.17 cm-1 and the (10022-00001) band of 12C160160at 5858.03 cm-1. The ana1ysis of this region of Venus' spectrum has relied on ca1culatedintenSities of these bands. We have recorded a substantia1 set of C02 spectra in thisregion using a 25 m base path White-type ceU and Bomem DA8 FTS. The absoluteintenSity measurements of transitions in these bands have been carried out. The resultson calculations of transition dipole moments. Herman-Wa1lis parameten and the bandintenSities of these bands will be discussed.

POSTER SESSION, N13

SPECTROSCOPY OF SHORT-LIVED SPECIES IN MILLIMETER_AND SUBMILLIMETER-WAVE REGION

ISAMU MORINO. AND KOICHI M.T. YAMADA, National In-stitute for Advanced Interdisciplinary Research, Higashi 1-1-4, Tskuba305-8562, Japan.

In the last couple of years, we have constructed two spectrometers in our instituteò onefor millimeter-wave and the other for submillimeter-wave region.

The submillimeter-wave radiation in the present system is produced by Russian BWOs(Backward Wave Oscillator). The BWO frequency is stabilized by a phase-lock loop usinga Shottky-type harmonic mixer of KOSMA, wh1ch mixes the radiation from a BWOwith that of a millimeter-wave synthesizer.b A part of submillimeter power is reflectedby a wire-grid beam splitter and directed to the absorption cell. The transmitted poweris detected by a liquid-helium-cooled InSb bolometer which is magnetically-tuned. Theperformance of the spectrometer has been tested by measuring the rotational spectra ofNH20H, NH2, and CF in 400-500 and 600-800 GHz region.

A millimeter-wave spectrometer using a Gunn oscillator has been constructed to observe

van-der- Waals complexes in supersonic jets. The supersonic molecular jet is produced byexpanding a gas mixture into a vacuum chamber through a 0.5 mm pin hole using a pulse

nozzle with stagnation pressure of -1 bar. The phase-locked millimeter-wave radiationfrom a Gunn oscillator is focused on the supersonic jet by a polyethylene lens and theD byanother lens onto the detector. Both source-frequency and jet-pulse modulatioD methodsare applied in order to improve the sensitivity and to reduce the distortioD of base linecurve. Test measurements of the I>-typerotatioDal spectra of Ar-COc have beeD carriedout and the resulted spectra will be presented. The submillimeter-wave experimeDts forsupersonic jet is now in progress.

4Domestic Research Fellow of Japan Science and Technology Corporation.bG. Winnewisser, Vib. Spedro.c., 8, 241 (1995); I. Morino, M. Fabian. H. Takeo, and K.M.T.Yamada, J. Mol. Spectro.c., 185, 142 (1997).

cM. Hepp, W. Jäger, I. Pak, and G. Winnewisser,J. Mol. Spedro.c., 176,58 (1996).

r POSTER SESSION,N14

INTERMOLECULAR INTERACTIONS IN THE OH+-HejNe OPENSHELL IONIC COMPLEXES PROBED BY IR PREDISSOCIATIONSPECTROSCOPY

OTTO DOPFER, DORIS ROTH, SERGEY A. NIZKORODOV,AND JOHN P. MAIER, Physical Chemistry, University 01 Basel,Klingelbergstr. 80, CH-4056 Basel, Switzerland.

Mid-infrared spcctra of mass-selccted OH+ -He/Ne open shell ionic complexes have been

recorded by photofragmentation spectroscopy in a tandem mass spectrometer. The Vl

vibration (OH strctch) and its combination band with the intermolecular bending vibration

(VI + Vb) havc bccn observed for both complexes at the level of rotational resolution. Theanalysis of thc spectra shows that the complexes have a linear proton-bound structurein their 3~- elcctronic ground states, with intermolecular center of mass separations of2.60 and 2.65 Å, respectively. The Vl vibrational origins are red shifted by 66.3 and

169.9 cm-1 from the corresponding monomer transition, indicating that the intermolecular

interaction increases upon Vl excitation. The fine structure of the Vl e~- +-- 3~-) andVI + Vb en +-- 3~-) transitions arising from the electron spin and vibrational angularJIlOlllentum of vb have been allalyzed in terms of a semi-rigid Hamiltonian including spin-

spin, spin-rotation, and l-type doubling interaction terms. The molecular parametersextracted from the molecular constants providc valuablc information on the radial and

Rngular part of the intermolecular potential energy surface in each considered vibrationalstate. The intermolecular interaction in OH+ -Ne is stronger than in OH+ -He, mainly due

to the larger polarizability of the rare gas atom.

POSTERSESSION.N15

OBSERVATION OF TiF+ BY VELOCITY MODULATION LASEItSPECTROSCOPY AND ANALYSIS OF THE [17.6]3ß - X31þSYSTEM

C. FOCSA1, B. PINCHEMEV, D. COLLET2 ANDT. R. HUET2, Laboratoire de Physique des Lasers, Atomes etMolécules, UMR CNRS, Centre d'Etudes et de Recherches Lasers etApplications, Université des Sciences et Technologies de Lille, 59655Villeneuve d'Ascq cedex, Fhmce1 Previously Laboratoirede Dynamique Moléculaire et Photonique, URACNRS 7792 Previously Laboratoire de SpectroscopieHertzienne, URA CNRS 2.9.

The molecu1ar ion TiF+ has been observed for the.first time using high-resolution spec-troscopy. The ions were produced in the positive column of an AC glow discharge witha gas mÎxture of He/TiF 4. A single mode cw dye laser along with the velocity modula-tion detection technique was used to record an absorption Spectrum in the spectral region16800 -18600 cm-1. The observed system was assigned to the 0 - 0 and 1-1 bands of the

[17.6)3 fj. - X31þ transition of TiF+. The rotational analysÎ8 of the main subbands has beenpeñormed up to J values equal to 77 and 56 for the 0 - 0 and 1 - 1 bands. rcspectively.Despite a careful search, no intercombination band was observed. A set of eft'ective molec-u1ar parameters has been determined, characterizing the v = 0, 11evels ofthe (17.6)3fj. andX31þ states. The spin-orbit constants A. and the vibrational constants w.,w.x. have been

estimated for both electronic states, as well as their equi1ibrium distances R. (1.7509(1)

and 1.7800(1) Å for tbe (17.6)3fj. and X31þ states, respectively).

POSTER SESSION, N16--J{IGlILY EXCITED ROTATIONAL DYNAMICS OF Ht

1. N. KOZIN, M. ROBERTS" MathematiC3Institute, University 01Wanuick, Coventry CV.4 7AL, UK; J. TENNYSON, Department 01PhysiC3and Astronomy, University CollegeLondon, Gower St., LondonWC1E 6BT, UK.

The evolutioll of lDolecular dynamics ullder rotational excitation has been studied throughthe analysis of slßall oscil\ations (vibration and precession) around positions of relative

equi1ibria (i.e. steady rotations). Relative equilibria (RE) are the stationary points ofIhc effeclive potel1tial function which incorporates both the potential function of theD10lecule al1d its rotatiol1al energy. For a long time this has been well understood for

diatomic molecules but the increase in dimensionality of the problem brings qualitatively

new fcatures. RE and their stabilities have been calculated for the Ht ion and its iso-

topic modificatiol1s. The global cIassical picture of rotational dynamics up to and aboveIhe dissociatiol1 limit have beel1 obtained under the assumption of an isolated electronic

groulld state. Several remarkable phenomcna have been observed:

.confirmation that for Ht, H20+ and 02H+ the lowest energy RE has linear geometryat sufficiently high values of the total angular momcntum J;

.the RE corresponding to the maxirnal rotational ellergy of the J-rnultiplets under-

goes a Hamiltolliall-Hopf bifurcation, i.e. the stability of two normal modes is lostsimultal1eoll.~ly;

. boulld alld quasi-boul1d cIassica1 trajectories above dissociation lirnit.

.othcr bifurcatiol1s of RE occur as J changes.

Possiblc consequel1ces for tbe analogous quanturn system wil1 be discussed. It was foundIhat thc bifurcation diagrarns as J increases for the sirnple pair potential and the recent

vcry accuratc potcl1tial " are qualitatively tbe same. It is anticipated that the approx-imation of an isolated electronic state is not valid especially as the energy approachesIhc dissociation limit. but it is believed that sorne of thc predicted phenomena should

ncvertheless persist.

"ß. M. OIN~:I.LI,O. L. POLYANSKYANDJ. TENNYSONJ. Chem. Phya.,103, 10433 (1995).

POSTER SESSION, N17

A SPECTROSCOPIC STUDY OF THE 70GeD. GERMANE ISOPO.TOMER IN THE 1410-1620 cm-I RANGE

CL. PIERRE, G. PIERRE, Laboratoire de Physique de l'Universitéde Bourgogne UPRESS-A 5027 Théorie des Systèmes Moléculaires etdes Phénomènes non Linéaires 9, Avenue Alain Savary, F-21011 Dijon-GedexFrance;E. B. MKADMI AND H. BÜRGER, AnorganischeGhemie, FB9, Universitãt GH, D-42097 Wuppertal, Germany.

Two spectra of the isopotomer 7oGeD. of germane have been recorded using a Bruker120 HR interferometer. Both spectra were recorded with an optical resolution "(MOPD)-Iof 3.3 x 10-3 cm-I giving line widths less than 4 x 10-3 cm-I. This r.orresponds tothe convolution of a Doppler-eß'ect Gaussian functipn with the instrumental line shape

function (V(2.1)2 + (3.3)2 = 3.9) in 10-3 cm-I.We study the 113band of the 70GeD. molecule. The analysis of the spectra was madewith a Hamiltonian expanded through the 5th order. More than 300 lines were assignedto rotational levels with J ~ 20 of the 113band and used in the analysis. The standarddeviation obtained was beUer than 3 x 10-3 cm-I. This work is in progress and theresults wiU be presented.

~-

POSTERSESSION.N18--gYPERFINE CONSTANTS AND HARMONlC FORCE FIELD OFCllLORYL FLUORlDE. FCI02

HOLGER S. P. MÜLLER, 1. Physikalisches lnstitut, Universitãt zuKõln, Zülpicher Str. 77, D-509S7 Kõln, Germany.

The rotational spectrum of FC102 has been reinvestigated in the microwave to submil-liIneter regions using microwave Fourier transform and conventional absorption spec-trOSCOpy.New and improved spectroscopic constants have been obtained for the iso-topomers FMCI02 and F37CI02. In particular, the complete quadrupole tensor and 19F,3501,and 37CI spin-rotation constants have been determined for the first time. Vibra-tional spectra have been recorded for six isotopomers of FCI02 isolated in a neon matrix.The data was used together with improved quanic distortion constants to improve theharmonic force field. The results will be compared with those for related molecules.

POSTER SESSION, N19 ,-INFRARED SPECTROSCOPY AND MOLECULAR PROPERTlES OpCHLOROSYL FLUORIDE, FCIO

HOLGER S. P. MÜLLER, 1. Physikalisches Institut, Universitãt zuKöln, Zülpicher Str. 77, D-50997 Kõln, Germany.

The in situ hydrolysis of CIF3 has been used to obtain rotationally resolved spectra of FCIOfor the first time. The CIO stretching bands (Vd centered at 1037.689 and 1028.552 cm-Ifor F35CIO and F37CIO, respectively, have been recorded with a resolution ofO.OO3cm-I.Strong a-type lines, and for F35CIO also much weaker &.type lines, have been assigned.Transitions with quantum numbers iarger than 70 and 20 for J and Kø, respectively,permitted the determination of precise spectroscopic constants. The derived properties,such as molecuiar structure and harmonic force field, wlll be discussed in relation to abinitio results and data from related molecules.

POSTER SESSION.N20--Or AND C02- BROADENED WATER IN THE 112 BAND

J,.. R. BROWN. AND R. A. TOTH. Jet Propulsion Laboro-tory, Califomia Institute of Technolo9Y,PaJadena, Califomia 91109;R.R. GAMACHE , Dept. of Environmental, Earth and Atmo-

spheric Sciences, University of MaJsachusetts Lowell, Lowell, MA 01854;CLAUDE PLYMATE, NOAO/National Solar Observatory, ThcsonArizona 85726.

Measured and ca1culated halfwidths and pressure-induced frequency-shifts at room tem-perature are reported for 02- and CO2-broadened H20 transitions between 1260 and2090cm-1. For this, calibrated spectra of the 112band of water were recorded at 0.0054CDI-1resolutionwith the McMath Fourier transform spectrometer located at the Kitt PeakNational Observatory f National Solar Ohservatory. For the ~+H20 data with transi-tions up to J' = 14 and Ka = 7, 50me 350 observed widths (HWHM) vary from 0.065 to0.006cm-1 fatm and the pressure-shifts fall between -0.0072 and 0.0049 cm-1 fatm. For theCXh+H20 data with transitions up to J = 13 and Ka = 5, the 250 widths vary from 0.212to 0.0313 cm-1 fatm and the pressure-shifts fall between -0.0386 and 0.0382 cm-1 fatm .Tbe ca1culation of tbe broadening coefficients uses tbe Complex Robert-Bonamy (CRB)formulation. Good agreement between measured and ca1culated halfwidths is observedexcept for narrow lines, for which the ca1culated values are too large. For C02-broadenedwater, the pairs of transitions involving the same rotational quantum (e.g. 202- 313and313- 202etc.) have shifts that are opposite in sign and often similar in magnitudej thisbebavior is not 50 prevalent in the 02-broadened shifts. This fact is confirmed by thecalculations.

POSTER SESSION, N21

MEASUREMENTS OF THE LINE STRENGTHS AND HALF_WIDTHS OF THE (2-0) AND (3-0) BANDS OF CO

M. FUKABORI,T. AOKI, AND T. AOKI. MeteorologicalResearchlnstitute. Tsukuba, lbaraki 305-0052, Japan; H. ISHIDA, AND T.WATANABE. Toray Research Center lnc., Otsu, Shiga 520-0842,Japan.

In order to exarnine the uncertainties of the line pararneters of the spectroscopic database.the absorption spectra of the (2-0) and (3-0) bands of CO in the near infrared region weremeasured with a high-resolution Fourier transform spectrometer at room temperature.

The line strengths and half-widths of CO were detennined by a non\inear least squarestechnique. We compared our results with the va\Ue8 compiled in the HITRAN databases.

The measured line strengths agreed well with the va\ues of HITRAN92 and HITRAN96within the experimental error for the (2-0) band of CO. The measured line strengths were

5% smaller than the HITRAN values for the (3-0) band of CO. The vibration-rotationcoupling functions of these bands were obtained and the coefficients of the Herman- Wallis

factors were compared with the va\ues reported by other investigators.Self-, N2-, and 02-broadened half-widths were measured. and air-broadened half-widthswere calculated with these values. We found that self-hroadened half-widths of CO deviates

from the va\ues of HITRAN96. while air-broadened half-widths of CO were very close tothe HITRAN96 values.

,POSTER SESSION, N22

FAR INFRARED SPECTRUM AND SPECTROSCOPICPARAMETERS OF SbD3 IN THE GROUND STATE

L. FUSINA, G. Dl LONARDO, Dipartimento di Chimica Fisicae Tnorganica, Università di Bologna, Viale Risorgimento 4, /-40136Bologna, Italy ;

H. BÜRGER, W. JERZEMBECK, Anorganische Chemie, FB 9,Univer.~itiit-Ge.~amthochschule,D-42097 Wuppertal, Germany.

Thc rotation spcdrum of deuterated stibine, SbD3, in the ground vibrational state was

r('('ordcd in thc rcgion betwecn 20 and 100 cm-1 at a resolution (1 / maximum optical path

diff.~rcncc) of 0.!){)23 CII1-1. 6.J = + 1, 6.K = 0 transitions werc measured and assigned

wilh 6 ~ J" ~ 29 and 0 ~ K ~ 27 for both 12ISband I23Sbisotopomers.

Thc data of cad. 1I1011'C1Ilcwerc analyzed togethcr with the J = 0, 1 rotational transitions

rI'\lortcd in thc litcratllre 1, and ground state combination diffcrenccs from thc analysis of

ll1.. high resollllion spedra of the stretching fundamental lJands. The theoretical models

adoptcd for thc analysis included 6.k = :1:3 or 6.k = :1:6 interaction terms and correspond

to lwo differcnt redllctions of the rotational Hamiltonian.

1. r. Hrlll1ing('r, E. L. ßccwn .Jr., alld W. Gordy. Phys. Rev A, 3, 122 (1971).

POSTER SESSION, N23

NONLINEAR SEQUENCE TRANSFORMATIONS IN THE DI-ATOMIC MOLECULAR SPECTRA CALCULATIONS

A.D. BYKOV, V.M. MIKHAILOV, M.A. SMIRNOV, Institute 01Atmospheric Optics, S8 RAS, Tomsk, Russia, 634055.

The high-order perturbation theory is now recognized to be powerful tool for solving dif-ferent quantum mechanics problems [1]. In the cases where the perturbation expansionsdiverge the specia1 summation methods should be used. As to the molecular highly ex-ited vibrationa1 rotationa1 energy levels calculations, the Pade, Pade-Borel approximationshave been a1ready employed to sum divergent series which serve as the effective rotationa1

Hamiltonian. This results in the satisfactory agreements with experiment for high J leve1s

as wel1 as high vibrationa11evels (see for instance [2]). It seems to be useful to apply thesemethods to investigate other molecular observåbles, such as dipole transitions probabili-ties, Stark and Zeeman shifts which can be also represented by power series within the

contact transformation method. The aim of the present contribution is to ana1yze the ap-plicability of the summatioll methods (which have been used for energy levels calculations)for solving IR and Raman intensity problems for transitions to the highly excited states

of the diatomic molecules. The two conceptions are taken into account in the ana1ysis ofrovibronic dependencies of observables for diatomic molecules:

(i) the ordering of vibrationa1-rotationa1 interactions in linked grouping system (3),which a110ws one to estimate the high-order terms in contact transformation method

(ii) nonlinear sequence transformations for the acceleration of convergence and the sum-

mation of divergent series [4].

The results of the numerica1 modeling of transitions effective dipole moments for some

diatomic molecules using Levin's nonlinear transformations will be presented.The authors acknowledge the support by Russian Foundation for Fundamenta1 Research(Grant N 96-03-33801).

1. B. Simon, Int.J.Quantum Chem., 21, 3 (1982)

2. J. èizëk, V. Spirko, and O. Bludský, J.Chem.Phus., ~, 7331 (1993)

3. V.M. Mikhailov, "In MW spectroscopy and Its applications", Scientific counsil on

spectroscopy, Acc.Sci. USSR, Moscow (1985)4. E.J. Weniger, Computer Phys. Report, 1!l, pp.189-371 (1989)

POSTER SESSION,N24

WIDTHS AND SHIFTS OF N2 BROADENED LINES IN (010)-(000)BAND OF H20

A. VALENTIN, CH. CLAVEAU, Laboratoire de PhysiqueMoléqulaire et Applications, CNRS Université Pierre et MarieCurie, Paris, France; A.D. BYKOV, N.N. LAVRENTJEVA,V.N. SAVELIEV, AND L.N. SINITSA, Institute 01 AtmosphericOptics, SB RAS, Tomsk, Russia, 634055.

N2 line broadening in (010)-(000) band of the H20 has been studied in 1850-2200 cm-Iregion.Thc measurements were made with the FOllrier transform spectrometer. The spectralresolution was 0.005 cm-I. Spectra at different pressures of sample (P(H20)=0.75-12torr, P(N2)=0-400 torr ) have beell recorded at temperature 258-299 K.The line half-width alld shift determinations were made by nOlllinear least-square fittillg ofthc Voigt cOlltour to the measured values of absorption. The linewidth and shift coefficientsof N2 broadened have bcen determined by fitting to measured values at different pressuresof saniple. Self-illduced line broadening was taking into account using the literature vaJues.CollisiollalJy illduced line narrowing has been takell into account by variation Doppler halfwidth in Voigt contour. For some lines narrowing parameter has been determined.Calculations of Nrinduced linewidth and shift coefficients were performed using theAnderson- Tsao-Curnuttc theory considering dipole-quadrupole, quadrupole-quadrupole,inductioll and dispersive interactions. Fairly satisfactory agreement between measuredand calculated linewidth coefficients has been found.Our results are compared with experimental data taken from literature.The temperaturc dependence of lineshift and width coefficiellts wil1be discussed.Acknowledglllrnts: The authors from Tomsk acknowledge the support by Russian Foun-dation for Fundamental Research (Grants N 98-02-16375, N 98-02-17772). This study hasbccn performed ill the framework of agreement betwccn CNRS and Russian Academy ofSr.iencc.

POSTER SESSION, N25

WIDE-PRESSURE RANGE STUDY OF THE WATER-VAPOR LlNESHIFTING IN 5000-5600 CM-1 REGION BY ARGON AND OXYGENPRESSURE

N.N. LAVRENTJEVA, A.M. SOLODOV, Institute 01AtmosphericOptics, SB RAS, Tomsk, Russia, 694055; G.T. FRASER, NationalInstitute 01Standards and Technology,Gaithersburg,MD 20879, USA.

The results of the measurements and calculations of the line shift coefficients of the 1'2+ IIJand 111+ 1'2 water-vapor bands by Ar and 02 pressure have been presented in this work.

The measurements were carried out at NIST, USA using BOMEM DA3.oo2 FT- spectrom.

eter at spectral resolution of 0.007 cm-1 and White-type cell with an optir.al pathlengthof 8405 cm. The pressure of water-vapor was varied from D.45 torr to 0.87 torr, and thepressure of the buffer gases ranged from 150 torr to 4000 torr. The values of shift coeffi.

cients for more than 100 water-vapor lines have been derived from recorded spectra, theyrange from 0.005 cm-1/atm to 0.02 cm-1/atm.

The calculations have been made using Anderson theory. Dipole-quadrupole, quadrupole-quadrupole, induction and dispersive interactions have been taken into account. There

was one fìtted parameter in calculation of the line shift coefficient - the polarizabilityin upper vibrational statc. which was determined by fìtting to some measured values ofshifting. Thc agreement of calculated and experimental data is fairly good. Rotationaldependence of the line shift coefficient is discussed.This work has been partially supported by the NASA Upper Atlllosphere Research Pro-gram and Russian Foundation of Fundamental Research (Grant N 98-02-16375).

POSTER SESSION, N26--ROTATIONAL ENERGY AND LlNE INTENSITY ANALYSES FORTØE FIVE FIRST VlBRATIONAL STATES OF THE WATERMOLECULE

k H. COUDERT, Laboratoire de Photophysique Moléculaire,C.N.R.S., Bât. 210, Université Paris-Sud, 91405 Orsay Cedez,France;R. LANQUETIN, AND C. CAMY.PEYRET, Laboratoirede Physique Moléculaire et Applications, Unité propre du C.N.R.S.,Université Pierre et Marie Curie, Tour 13, BoÎte 76, 4 Place Jussieu,75252Paris Cedez 05, france.

The 6rst part of this paper deals with a global analysis of the rotationa11eve1s of water

helonging to the (000), (010), (100), (001), and (020) states. The data set consideredconsists of experimenta1 rotational energies which have been obtained for these five vi-brational states using high-temperature flame spectra. The theoretical treatment used isa moditìed version of the bending-rotation Hamiltonian formalism8 in which the strong

Fenni-type and Coriolis-type interactions occurring in the first triad, already considered'in the Watsonian approach, are included. Pre1iminary ana1yses show that the theoretical

formalism alloW8 us to reproduce the experimenta11eve1s up to J = Ka = 18 for al1 five vi-

brational states. However, a few cases of large Obs. -Calc. dift'erences, which are probablyrelated to interactions between rotationa11eve1s of the first triad and those of the second

triad are remaining.The second part of this paper will describe an attempt at determinating the dipole momentfunction of water through a line intensity ana1ysis. The data set considered consists of

transitions belonging to various bands involving vibrationa1states of the fìrst triad.c,cI Inthis second analysis, (an extension in the framework of the large amplitude formalism of

the approache initial1y used for the first triad) line-strengths were determined evaluatingthe dipole moment matrix elements with the help of the spectroscopic constants obtainedin the previous analysis. Work is still in progress, but we hope to be able to compare our

results with those obtained through ab initio calculations by Jensen et al.l

OL. H. Coudert, J. Mokc. Sputro,c. 181, 246 (1997)..J.-M. Flaud and C. Camy-Peyret, J. Molec. Sputro,c. 51, 142 (1974).cR. A. Toth, J. Opt. Soc. Am. B 10, 1526 (1993).dR. A. Toth, J. Opt. Soc. Am. B 10, 2006 (1993).'J.-M. Flaud and C. Camy-Pcyret. J. Molec. Sputro,c. 55,278 (1975).Ip. Jenscn. S. A. Tashkun, and Vl. G. Tyuterev, J. Molec. Sputrosc. 168,271 (1994).

POSTER SESSION, N27 -PRECISE MEASUREMENT OF THE ROTATIONALSUBMILLIMETER-WAVE TRANSITION OF HCI AND DCl INTHEIR V = 0,1 STATES

SERGEI P. BELOV, Institute 01 Applied Physics RAS, UljanovaStr. 46, 603600 Nizhny Novgorod, RUSSIA; THOMAS KLAUS ANDGISBERT WINNEWISSER, 1.PhysikalischesInstitut, Universität zuKöln, Zülpicher Str.77, D-50937, Cologne, Germany.

High-resolution sub-Doppler Lamb-dip measurements were performed on the low-J rota-tional transitions of the hydrogen cloride isotopomers H35Cl, H37Cl, D35Cl and D37Cl inthe submillimeter-wave region up to 646 GHz with Cologne terahertz spectrometer. Forthe J = 1 - 0 transitions of the two HCl isotopomers the' hyperfine splitting due to the

hydrogen nuclear spin-rotation interaction is resolved. Furthermore Doppler-limited 1inesof the DCl J = 3 - 2 transition around 965 GHz as well as hyperfine-resolved rotationa1transitions in the first exicited vibrational state were recorded up to 1.22 THz. The new

frequencies were analyzed in global fit together with FIR data and the precise data frommolecular beam electric resonance measurements yielding a set of mass-invariant rotational

parameters including the high orders of the vibrational and rotational expansion COefIì-cients of the clorine and hydrogen hyperfine interactions. The details of the measurements

and the results of the fit will be presented.

This work has been supported in part by the Deutschen Forschungsgemeinschaft (DFG)via grant SFB 301.

POSTERSESSION, N28-LINE SffiFT AND LINE BROADENING IN THE &"lBAND OF H2S

A. KISSEL, H.-D. KRONFELDT, Optische" Institut der Tech-nischen Universitãt Berlin, Hardenbergstrasse 36, Sekr. PN 0-1,10623 Berlin, Germany; B. SUMPF, ELIGHT Laser Systems GmbH,Warthestrasse 21, 14513 Teltow, Germany; B. A. TIKHOMIROV,Yu. N. PONOMAREV, Institute 01 Atmospheric Optics SB RAS,Akademicheskii Av. 1, 634055 Tomsk, Russia.

This paper summarizes the final results of our investigations concerning line shift and linebroadening of absorption lines in the &"lband of H2S due to collisions with noble (He, Ne,Kr, Ar, Kr, Xe) and molecular (02, N2, H2, D2, C02) gases. The measurements weree&fried out using a three channel lead salt diode 1aser spectrometer with an resolutionbetter than 5 . lO-~cm-1 and two multipass Herriott cells. Altogether 11 lines fromthe P-branch (3 ~ J" ~ 8, 2 ~ K~ ~ 8), 19 lines from the R-branch (2 ~ J" ~ 11,o ~ K~ ~ 11), and 4 lines from the Q-branch (8 ~ J" ~ 10, 7 ~ K~ ~ 9) wereinvestigated. The dependencies of the detennined broadening and shift coeflìcients on therotational quantum numbers J" and K~, on the polarizability of the noble gases, and onthe quadrupol moment of the molecular gases are discussed.

The Project is supported by the "Volkswågen Stiftung" , A. Kissel thanks for a "NaFoeG"grant.

POSTER SESSION, N29 ,FINE STRUCTURE PHOSPHORESCENCE SPECTRA OF POLY.CHLORINATED DIOXINS

V.G. KLIMENKO, E.A. GASTILüVICH, AND R.N. NUR-MUKHAMETüV, Karpov lnstitute 01 Physical Chemistry, ul.Vorontsovo Pole 10, Moscow, 109064 Russia.

Toxic polychlorinated dibenzo-p-dioxins have been the subject of great concem for manyenvironmentalists and analysts in recent years. The method based on the fine structure

luminescence spectra of Sbpol'skii bas bigb sensitivity and selectivity and is very promisingfor tbe analysis of tbese compounds.1

Tbe present work is devoted to research of quasi linear pbosphorescence spectra of dibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin and octacbloroäibenzo-p-dioxin at 4.2 witbin

80lid bydrocarbon matrices. IR and Raman spectra was investigated and vibrations in tbeground electronic state were calculated semiempirically. On tbe basis of these data the

multiplet and vibronic structure of their pbospborescence spectra was analyzed. Tbeeffect of chlorine substitution on tbe forrns and frequencies of molecular vibrations in tbe

ground electronic state and on tbe energies of excited erlectronic states was studied. It was

establisbed, tbat in tbe course of tbe increase in tbe number of chlorine aOOrns tbe spin-orbit coupling in tbe lowest triplet state changes insignificantly, wbile tbe contribution ofvibronic-spin-orbit coupling to tbe pbospborescent transition of dioxine molecules increasesgreatly.

This work was supported by Russian Foundation for Basic Researcb, project no. 96-03-34089.

1. V. G. Klimenko, R. N. Nurmukhametov, and A. A. Stekhin, Dokl. Ross. Akad. Nauk,336. 489 (1994).

, POSTER SESSION, N30

MEASUREMENTS OF CO2 CONCENTRATION USING A NEAR IN-FRARED EXTERNAL CAVITY DIODE LASER ALONG AN ATMO-SPHERIC OPEN PATH

M. LARZILLlERE, D. INARD, S. TRANCHART, Laboratoirede Physique Atomique et Moléculaire, Université Laval, Québec, Qc,Canada, G1K 7P4; L. VARFALVY, Hydro-Qubec, 75 Blvd RenéLévesque Ouest, Montréal, Qc, Canada, HflZ lA4.

Diode laser secolld derivative modulation spectroscopy combined with an open atmosphericpath is a well suited technique for greenhouse gases monitoring above wide areas. Wereport measurements of the atmospheric C02 concentration near 1.573 /1m performedwith a near illfrared spectrometer based on a commercial extemal cavity diode laser.Wavelellgth modulation spectroscopy and second harmonic detection were implemented.With an opell path of 326 m, the absorption sensitivity of this spectrometer was aboutof 9 x 10-4. Futllre improvements will be suggested 10 increase the sensitivity of thisapparatus in ordcr to measure gases ftuxes above artificiallakes.

POSTER SESSION. N31

LIF SPECTRA OF AlNC/AICN OBSERVED IN SUPERSONIC EX-PANSIONS

MASARU FUKUSIMA, Faculty of Infonnation Sciences, Hi-roshima City University, Hiroshima 731-3191"Japan.

Prior to experiments, ab initio ca1culations of AINCI AICN molecules have been carriedout within CCD/6-31G(d) and QCISD/6-311+G(3df) levels. These ca1culations yieldedspectroscopic predictions usefu1 for spectral searching, since no information was avail-able for tþe excited state. As reported recent1y1, it is confirmed that AINC is the lowerIying species in the ground state, Iying 2000 cm-1 below AICN within the QCISD(T)/6-311+G(3df) leve1. One of the new findings of the present computational work is thatthe singlet excited state of AINC/AICN is bent while the singlet ground states are linear.Guided by the predictions, we have observed, for the first time, the 1A' - X11:+ electronic

transition of AINCI AICN in UV region using the laser induced ßuorescence ( LIF ) tech-nique.. The molecules were generated in an Ar plasma produced by laser ablation. Thefragments from CH3CN in the Ar plasma were used as CN sources and AI was producedby laser ablation from a metallic Al surface. We have measured the LIF excitation spec-trum, LIF dispersed spectra from single vibronic levels (SVL), and LIF temporal profiles.The dispersed ßuorescence (DF) spectra show two kinds of vibronic bands: sharp andcongested. The vibrational frequencies obtained by the vibronic structure analysis of thesharp bands show good agreement with those predicted from the ab initio calculations.Based on the agreement, the spectral carrier is assigned to AINC/AICN. The linewidth,-0.04 cm -1, used in these studies preclude resolution of the rotational structures of the

vibronic bands of the excitation spectrum. The ßuorescence time profiles follow the laserpulse, indicative of the ßuorescence decay lifetimes shorter than the laser pulse width,-10 ns. Since AI atomic lines, 2S - 2P, are observed in some of the DF spectra, thepossibility of excited state predissociation is suggested. The vibronic structures consistingof the congested bands in the DF spectra show AI -CN stretching progressions startingat 1364 and 2710 cm-1. These structures have not been interpreted yet, but it will bediscussed in the presentation.M. F. is thankful to M. Sota, T. Wada, and M. Kato for providing the favorable researchconditions of Advanced Tecbnology Research Center, Mitsubishi Heavy lndustries, LTD.

1. B. Ma, Y. Yamaguchi, and H. F. Schaffer III, Mo1. Phys. 86, 1331 (1995).

rPOSTER SESSION, N32

ROTATIONAL SPECTRUM OF D2CO

R. BOCQUET, P. DREAN AND J. DEMAISON, Laboratoirede Physique des Lasers, Atomes et Molecules, UMR CNRS Univer-sité de Lille 1, 59655 Villeneuve d'Ascq Ceder, A. FRIEDRICH,L. MARGULES AND H. MAEDER, Institut Jür PhysikalischeChemie, Christian-Albrechts-Universitãt, D-2409S Kiel, Gennany;M. BEAKY ANDG. WINNEWISSER, 1. Physikalisches lnstitut derUniversitãt zu Köln, Zulpicher Strape 77, D-50937 Köln, Gennany.

Formaldehyde is the most extensively studied nonlinear tetratomic molecule. It is abun-dant in illterstellar space and its isotopic species. including D2CO, have been detected inseveral molecular clouds. It is aISOa benchmark molecule Corab initio calculations andits potcntial surCace has been reccntly determined several times. But, despite the greatnumber oCspectroscopic studies, the molecular parameters have not yet been accuratelydetermined. For this reason, we have remeasuredthe rotational spectra oCH2coa andD2CQ. The results CorD2CQ will be presented and discussed in this poster.The spectrum was measured in Kiel between 4 and 26.9 GHz with Fourier transCormmicrowave spectrometersj in Lille between 170 and 470 GHz with a millimeterwave spec-tromcter using BWQ's as sources and an InSb bolometcr as a dctector, and bctween 800and 2500 GHz with a Car inCrared laser sidcband spectromcterj and in Cologne between570 and 670 GH1. and 800 to 970 GHz with thc Cologne terahcrtz spectrometer usingBWQ's as Cundamcntal Crequcncysources and an lnSb bolomcter Cordetection.

"R. Bocquet, J. Demaison,L. Poteau, M. Liedtke,S. Belov,K. M. T. Yamada, G. Winnewisser,C. Gerke, J. Gripp, alld Th. Köhler, J. Mol.Spedro$c., 177, 154(1996).

POSTER SESSION, N33

QUANTUM STATES OF Ht AT DISSOCIATION

R. PROSMITI, H .Y. MUSSA, O. L. POLYANSKYANDJ. TENNYSON, Department 01Physics & Astronomy, University Col-lege London, Gower Street, London WCIE 6BT, UK.

3D variational calculations are presented for the ftoppy Ht molecule up to its dissociation.Such calcu1ations represent a computational grand cha11engedue to: (i) high density ofbound states, (ii) ftoppiness of Ht, which leads to numerical diflìculties.These calcu1ations have been performed using a para11e1izedDVR based program ø portedto massively para11el (MPP) machines in a manner appropriate for tackling the compu-tationa1 problems. The V ES potentia1 ð used here, has been designed Cor studying spec-

troscopy oC high-lying bound states and reaction dynamics. It thereCore describes reliablythe dynamics oC Ht at dissociation.The above calculations wil1 be used to compute synthetic spectra in nt'.ar-dissociation

region as a step in a direct Cully quantal attack on the infrared Ht photodissociation

spectra oC Carringhton and co-workers c.

"H.Y. Mussa, J. Tennyson, C.J. Noble and R.J. Allan, Comp. Phys. Comm. 108,29-37 (1998).'R. Prosmiti, O.L. Polyansky and J. Tennyson, Chem. Phys. Lett. 231,107-114 (1997).<A. Carringhton, I.R. McNab and Y.D. West, J. Chem. Phys., 98,1073 (1993).

POSTER SESSION, N34

INFRARED DIODE LASER SPECTROSCOPY OF THE CCO RADI-CAL AROUND 1950 CM-1

N. MOAZZEN-AHMADI, Department 01PhysiC$, University 01 Leth-bridge, Lethbridge, Alberta, T1K 9M,4, Canada; R.T. BORÉ, Depart-ment 01 Chemistry, University 01 Lethbridge, Lethbridge, Alberta, T1K9M,4, Canada.

The infrared spectrum of the CCO radical in tbe gas pbase has been studied using a tunable

infrared diode laser spectrometer. The CCO radical was produced using a flowing mixtureof carbon suboxide and helium subjected to a hoUow-cathode discharge. The spectral

region between 1920-1990 cm -1 was probed. The 111, 111+ 1"2-1"2, 2111-111, and 111+ v" - v"

in the ground electronic state and the 111band of the long-lived ã 11::.electronic state bave

been measured and rotationally analyzed. The band origins for 2111- 111and 111+ v" - v"were determined to be 1941.85761(54) cm-1 and 1936.79402(56) cm-1, respectively. Tbe

band origin for the V1 band of the ã 11::.electronic state is 1942.8515(25) cm-1. Tbis isclose to the value 1944(97) cm-1 determined previously from photoelectron spectroscopyof the CCO-.

POSTER SESSION,N35

SUB-DOPPLER MEASUREMENTS OF CO ISOTOPOMERS

F. LEWEN, G. KLAPPER, R. GENDRIESCH, AND

G. WINNEWISSER, 1. Physikalisches Institut, Universität zuKöln, D-50997 Köln, Germany.

High resolution Lamb-dip measurements on the J = 2 +- 1 rotational transition (near

230 GHz) of the carbonmonoxid isotopomers 12C160, 12C180, 13C160 and 13C180 wereperformed using phase stabilized backward wave osciIJators (BWOs). With a newlydeveloped phase stabj)jzation circuit for the BWO the FWHM linewidth of the BWOwas determined to be 0.08 Hzl with a minimum stepsize of the spectrometer of 10 Hz.Lamb-dip spectra are measured with a linewidth of only 16 kHz at 220 GHz.

For the two 13CO isotopomers, the hyperfìne splitting due to the carbon nuclearspin-rotation interaction could be resolved for the first time leading to the determinationof the interaction constant, Cr. .

The precise Lamb-dip frequencies were analyzed together with additional Doppler_limited measurements and data taken from the literature in a global fìt yielding a new setof isotopically invariant parameters. The hypernne interactions of the 13C and 170 werealso included in the global analysis.

The new set of molecular parameters provides highly accurate frequency predictionsthroughout the entire submm-wave region, for all CO isotopomers.

This work was supported by the Deutsche Forschungsgemeinschaft (DFG) via grant SFB-

301 and through grant Wl 391/7-1. In addition we want to thank the Ministry of Scienceand Technology of the State Nordrhein-Westfalen for support.

I F. Lewen, R. Gendriesch, 1. Pak, D. Paveliev, M. Hepp, R. Schieder, G. Winnewisser,Rev. Sci. Instrum. 69, 32-39 (1998)

POSTER SESSION, N36--røE GROUND VIBRATIONAL STATES OF DrSe and HDMSe(M==82, 80, 78, 77, 76)

Q.N. ULENIKOV, G.A. ONOPENKO, ANDN.E. TYABAEVA,Laborotory 01Molecular SpectroSCfJPy,Tomsk State University, 634050,Tomsk, RussiaLaborotory 01 Molecular SpectroSCfJPy,Tomsk State Uni-versity, 634050, Tomsk, Russia; H. BÜRGER, W. JERZEMBECK,Anorganische Chemie, FB9, Universitãt-Gesamthochschule, D-42097Wuppertal, Germany; J.-M. FLAUD, PH. ARCAS, Laboro-toire de Photophysique Moleculaire, CNRS, Universite Paris Sud, Cam-pus d'Orsay, Bat.210, 91405 Orsay Cedex, France.

High resolution (0.0027 cm-1) Fourier transform spectra of the D2Se and HDSe molecule(both 88 natural and 80Se monoisotopic samples) have been recorded between 600 and1900cm-1. The analyses of the 1OOl,\11and lIJ bands of D2Se and of the 1OOl,\It and 2100lbands of HDSe, which appear in this spectral region, have been carried out for the fìveisotopomers both of D2Se and HDSe. These analyses provided precise ground state com-bination differences for each band, which were then merged and fìtted using an A-typeWatson Harniltonian in Ir representation. The fìts which reproduced the ground statecombination differences to within the experimental accuracy (1 - 2 X 10-4 cm-1 depend-

ing 00 the isotopic abundance) led to the determination of precise sets of Hamiltonianconstants up to octic terrns.

POSTER SESSION, N37

THE ELECTRONIC SPECTRUM OF C7": RELEVANCE TO ASTRO-PHYSICS

DAVID KIRKWOOD, MAREK TULEJ. MIKHAIL PACHKOV,OTTO DOPFER, JOHN MAIER, Jnstitut für PhysikalischeChemie, Universitãt 8asel, 8asel, Switzerland.

The electronic spectrum of the linear carbon chain anion C7" has been measured in thewavelength range 400 - 700 nm. Resonant two colour electron photodetachment spec-

troscopy was used to record the origin and six vibronic bands of the A2nu +- x2ng elec-tronic transition in the gas phase. The observed linewidths of the bands are 1 cm-1,and they are therefore sufficiently narrow to enable a meaningful comparison with thetabulated Diffuse Interstellar Bands (DIBs). Juxtaposition of the experimental data withthe astrophysical observations evidence good correlation for the bands of C7". with allvibronic modes overlapping DID positions with congrùous intensities. The astrophysicalconsequences of this result force a rlH!valuation of the role of anions in the interstellarmedium.

, POSTER SESSION. N38

BENCHMARK AB INITIO POTENTIAL CURVES FOR THE FIRST-RQW DIATOMIC HYDRIDES AH (A=Li-F)

JAN M. L. MARTIN, Department olOrganic Chemi8try, Weizmann/nstitute 01Science, /L-76100 Re~ovot, /srael.

An ab initio calibration study has been carried out on the ground-state potential curves of

thc AH diatomics (A=Li-F) using coupled c1uster (CCSD(T)) and full configuration in-tcraction (FCI) methods, basis sets of up to to spdf ghi quality, and inc1usion of inner-shellcorrelation. At the highest levels of theory considcred, r. and W. of the first-row diatomic

hydridcs can on average be reproduced to within 0.0002 Å and 1 cm-I, respectively: thefirst four to six cxpcrimental vibrational band diß'erences G(n) - G(n - 1) are likewise re-

produced to withill about 1 cm-I without any empirical adjustment. The CCSD(T) basissct limit systcmatically overestimates W. by 4-9 cm -1 and underestimates r. by 0.0003-0.0006 Å. Highcr anharmonicities exhibit pronounced basis set sensitivity, which is marked

ly reduced upon uncontracting the basis set. For the light diatomic hydrides LiH, BeH,anrl BH, the intrillsic error is found to be comparable to or smaller than the nonadiabatic

elfects. Rcviscd spcctroscopic constants are proposed for BeH. BH is predicted to have an

IInllsnally largc nonarliabatic contriblltion of about 0.0025 Å to its bond length.

POSTER SESSION, N39

HIGH RESOLUTION OVERTONE SPECTROSCOPY OF PROPYNE IN THEVISmLE RANGE : EVIDENCE OF LINE BROADENING AND ROTATIONALANALYSIS.

A. CAMPARGUE

Laboratoire de Spectrométrie Physique. Université Joseph FOllrier de Grelloble,B.P. 87, 38402 Saint-Martin-d"Hères Cedex.

The absorption of propyne (CH)-C..C-H) has been recorded by Intracavity LaserAbsorption Spectroscopy, in the range of the VCH= 4 and 6 acetylenic overtonetransitions. In agreement with previous observation (1, 2], a partly resolved rotationalstructure is observed at room temperature for these two bands This is a unusualsituation for a relatively large molecule in an energy range where the density ofvibrational states is considerable (104/cm'l in the range ofthe VCII= 4 level). This featureresults of the isolationof the acetylenicCH stretch from the other vibrationalmodes. Theobserved rotational structure will be analyzedand discussed. Moreover, in the case ofthe VCH= 6 overtone band near 18500 cm.I, the line profile ana\ysis has evidencedallhomogeneous broadening 01 abollt 0.1 cm-I which will be discussed in relation withintramolecularenergyredistributioninto the dense rovibrationalbath.

[t) Z. Lin. K. Boraas and 1.P. Reilly. 1. ofMolec Spectrosc. 156.142-153 (1992).

(2) RR Hall. Ph.D. Thesis. Rice Univcrsity. Tcxas. 1984.

POSTER SESSION,N40

l'tIONOMER-DIMER EQUILlBRIA IN FULLERENE SYSTEMS

GEORGE KHAIRALLAH AND J BARRIE PEEL.

SdlOol o.f Chelllislry. /"0 7i"Obe (/l1i\'f!rsi~r, Blllldoora, J/cloria 3083, A lI.wralia.

The radical anion species C70(CN)i- is observed in the Electrospray Mass

Spcctromctryof C70/ CN"' solutionsa. but in thc analogous CóO/ C~ system b,c, thc

dimeric analog [C60(CN)2]22- appears to dominate thc mass spectrum The carbon

natural isotope distribution as measured suggests that there is possibly an equilibrium

between dimer and monomer. according to

In the C 70 / CN"""system the analogous dimer concentration appears to be quite low,

I

I

suggesting a relatively Icss reactive radical anion C70(CN)2,- Calculations at the AMI

semiempiricallevel have been used to compare the structures and stabilities of these

monomer and dimer adduct species of C60 and C70

a G.Khairallahand J.BPeel. Cyano Adduct-anionsof C70 . ElectrosprayMassSpectrometric Studies, J. Phys. Chem. A, !Q1. 6770-4 ( 1997)

b G.Khairallah and J.B.Peel. Cyano Adduct-anions of [60]Fullerene observed byElectrospray Mass Spectrometry, J Chem. Soc. Chem. Commun., 253-4 (1997)

c G.Khairallah and J.B Peel. Identification of Cyano Dianions of C60 by Electrospray

Mass Spectrometry, Chem Phys. Lett. 268. 218-22 (1997)

POSTER SESSION, N41

CONFORMA TIONAL PROPERTIES OF 2-CYCLOPROPYLIDENE-ETHANOL AS STUDIED BY MICROWAVE, INFRARED ANDRAMAN SPECTROSCOPY AND BY AB INITIO COMPUTATIONS

J,.'

STEFAN BRÄSEa, PETER KLÆBOEb, K.-M. MARSTOKKb, ARMIN DE

MEIJEREa. HARALD M0LLENDAL b ANDCLAUS J. NIELSENb

aGeorg-August-Universität, Tammannstrasse 2, D-37077 GöttÙlge'll,Gerll/cII/Y;

bDepartment ofChemistry. The University ofOslo. P. O. Box 1033 Blindem. N-0315Oslo. Norway

The microwave spectra of 2-cyclopropylideneelhanol, (CH2)2C=CH-CHpH. and one

deuterated species (hydroxyl group) have been investigated in the 23.0 - 39.0 GHz

spectral region at 263 K. One confonner denoted Skew 1 was assigned. In Ihis rolamer

the C=C-C-O dihedral angle is 1220from syn (00) and thc C-C-O-H dihedral angle is

660from syn. The hydrogen atom of the hydroxyl group forms a weak intramolecular

hydrogen bond with the 1teleclrons of the C=C double bond. The gas-phase IR spectrum

in the OH slretching region revea1ed a broad and complex band at a ralher high

wavenumber. This absorplion split imo three bands presumed to bclong 10 two

confonners with intemal hydrogen bond and one without. whcn Ihe compound was

isolated in argon matrices at 5 K. Large shifts were observed belween the IR speclra of

Ihe amorphous and cryslalline solids al liquid nilrogen temperature due to hydrogen

bonding. Certain weak IR and Raman bands present in the amorphous or liquid phases

vanished in Ihe crystal and are altributed 10 one or morc additional conformers in the

liquid. Somc IR bands in the range 3670-3630 cm.I, presenl in Ihe argon matrix speclra at

5 K of a ca. 550 K vapour deposit, vanished after annealing and were tenlalively

auributed to high energy confonners. From temperature variations in thc Raman spectra

of the liquid Skew 1 was estimated to be 2.5 t 0.6 kJ mol.1 lo\Ver in enthalpy Ihan olher

confonnations. The experimenlal work has been assiSled by ab illitio compulaliol1s al Ihe

MP2/6-31G" level of theory.

POSTER SESSION, N42

SEMICLASSICAL DYNAMlCS OF NARROW AND WlDE WAVEPACKETS IN ONE AND TWO DlMENSIONS

N. E. KUZ'MENKO,V. V. ERYOMIN, AND 1. M. UMANSKII,Department 01 Chemistry, Moscow State University, Leninskie Gory,Moscow 119899, Russia.

We present the semiclassica1 theory for one- and two- dimensional motion of wave packets

excited by ultrashort light pulses. Tbe theory is based on tbe Green's function approacbcombined with the primitive semiclassica1 representation of stationary wave functions. Tbetheory for narrow wave packets containing few vibrational components was constructed

by expanding the action in energy near tbe center of tbe wave packet. In tbe case of wide

packets composed of many vibrational states tbe cIosed-Corm expressions Cor wave packetsare based on the PoÎS80n summation Cormula. Using tbe developed tbeory, we studied tbe

spatialloca1ization of tbe wide wave packet excited in a diatomic molecule under tbe actionof tbe delta-like pump pulse 1. We sbowed tbat only Cew oC many vibrational components

contribute to wave packet at a given moment and p08ition. It was aISO Cound tbat tbeshape oC tbe packet strongly depends on tbe number oC initial vibrationallevel, wbereas

the spectral widtb of tbe packet is confined by a limited range of frequencies, wbich isdetermined by the shape and p08ition of electronic terms. Tbe tbeory was applied to the

spectrally narrow wave packet excited in two-dimensional molecular system in the absenceof mode coupling. It was shown tbat time dependence oC probability distribution at any

fixed point of the packet trajectory corresponds to tbe temporal sbape oC the pump pulse.ThiR result is similar to that obtained in one- dimensional case. The localization area oC

the packet as well as the coordinate dependence of its amplitude was establisbed. Tbiswork was supported by Russian Foundation Cor Basic Research (Grant no. 96-03-34398).

1. 1.M. Umanskii, V. V. Eryomin, and N. E. Kuz'menko, Zb. Fiz. Kbimii., 72, 907 (1998).

POSTER SESSION,N43

MULTISPECTRUM FITTING TECHNIQUE FOR DATA RECORDING WITHFOURIER TRANSFORM SPECTROMETER.

APPLICA TION TO N]O AND CH4.

L. REGALIA , J-JPLATEAUX, C. BOUSSIN ANDA BARBE

Grollpe de Spectrométrie Moléclllaire et Atmosphériqlle. Eqllipe associée all CNRS

UPRESA- CNRS 6089, UFR Sciellces. BP 1039,51687 Reims cedex 2, Frallce

We have developed in our laboratory a least-square fitting technique for the simultaneous

fit of several spectra to obtain both a significantly time-saving in the data reduction and

an improvement on the accuracy of spectral parameters retrieved from spectra recorded

by Fourier Transform Spectrometer (1).This technique provides simultaneously intensities

and broadening coefficients with more realistic error bars. We describe brief1y the

algorithm of our software allowing the analysis and the visualisation of several spectra

simultaneously We present two studies on the measurements of intensities and self-

broadening coefficients of molecules N20 and CH4. ln the first study related to the 2vI

band of N20. we have validated the technique with three spectra and compared the

results with those provided by iterative least-square fitting methods(2.3).The second one,

with six spectra in the spectral region 5500-6180 cm.I, really turns the multispectrum

fitting technique to advantage. lndeed the improvement in the accuracy of a given

spectral parameter is related to the number of spectra containing information on it. We

have also compared our intensity measurements with those obtained by 1.S. Margolis(4)

with the self-broadening coefficients have been measured for the first time(5).The used

spectra have been recorded with the Fourier Transform Spectrometer (working in

stepping mode) built at Reims in our research team(61.ln conclusion, this new software

and the improvements in the interferometric data acquisition(7) (better localisation of zero

transmittance level). allow us to obtain spectral parameters with a better absolute

accuracy.

1. J-J Plate.1ux. L. Régalia. C. Boussin and A. Barbe. sllbmilted 1998

2. L Régalia. X. Thomas. A. Hamdollni. and A. Barbe.J.Q.S.R.T.. 57. 435 (1997)

3. R.A. Toth. Appl. Opl. 32.7326 (1993)

4. J.5. Margolis. App/. Opl. 27. 4038 (1988)

5. C. Boussin. L. Régalia. J.J. PLateaux and A. Barbe. sllbmiltcd to JMS (1998).

6. J-J. Plateallx. A. Barbe and A Delahaigllc, Speclrochim. Acla. 51A. 1153 (1995)7. L. Régalia. thesis (1996)

290

POSTER SESSION,N44

FOURIER SPECTROSCOPY DICKE NARROWING MEASUREMENTS

ON WATER VAPOR V2 R-BRANCH LINES.

C. CLA VEAU, D. HURTMANS. A. HENRY, AND A. VALENTIN.

Laboraloìre de Physique Moléculaire el Applicalìons, CNRS. Université P. el M Curie.-1Place Jussieu, Tour 13, 75252 Paris cedex 05, France.

Recently, it has been possibleto detennine the apparatus function shape for the

Fourier spectrometer built in the laboratory within a precision of a few thousandths.

even when the apparatus function width is of the same order of magnitude as the

Doppler one in the 5 micrometer region. Such a precision allows analysis of the

pressure broadened absorption line profiles and has been used to evidence the

deviations from the Voigt profile in the observed R-branch lines of the water vapor V2

band.

For absorption lines with high values of the J. K.. K.,quantum numbers, the

pressure broadening parameters are rather smal1for H20 and it is possib1eto observe

the Dicke narrowing efTectin a large range (from 40 to 300 torr) of the tota1 pressure

(H20 + bufTergas). for difTerentperturbinggases (N2.He. Ne, Ar and Kr).

The dynamic friction parameter 130associated with the Dicke narrowing has

been detennined \vith a precisionof 5 to 20 percents according to the collision partnei:

The measured mean va1ueagrees well with the va1ue ßOditrdeduced from diffusion

measurements.

This work is, to our knowledge. the first one achieved on this efTectusing a

Fourier spectrometer.

POSTER SESSION,N45

Microwave Fourier Transform Spectroscopy of cycliccompounds containing a sulfur atom

S. KASSI. L. MARG!lLES. D. PETITPREZ AND G. WLODARCZAK.

Laboratoire de Physique des Lasers. Atomes et Molécules (UMR CNRS)

and CERLA. Bat. P5

Université des Sciences et Technologies de LilIe

F-59655 VilIeneuve d'Ascq Cédex. Francc.

Some recent rcsults obtained with our newly built microwave

Fouricr transform spcctrometer. operating in the frequency range 5-20 GHz.

are presented.

Two cyclic compounds. tetrahydrothiophen (C4HgS) and thietan

(C3H6S) have bccn investigatcd: the rotational spectra of isotopic species

(13C. 34S and 33S) have bcen analY7.edand a geometrical structure derived.

Thc experimental quadrupole coupling constants for 33S are compared to abinitio calc111atcd values. For thietan thc first excited state has also been

studicd.

We also present a preliminary analysis of the spectrum of the

tcu'ahydrothiophen - Ar complcx: the rotational constants for thc main species

were dctclmined. togclhcr with the ql1artic ccntrigugal distonion constants.

POSTER SESSION.N46

HIGH-RESOLUTION INFRARED SPECTROSCOPY

USING SYNCHROTRON RADlATION

MATIHEW S. JOHNSON. Un;vers;ty o[ Copenhagen, Kem;sk Inst;tut.

Lab 5, Un;versitetsparken 5. DK-2100. Kobenhavn ø. Denmark:

BENGT NELANDER. Un;vers;ty o[ Lund. Kem;centrum.

Thermochem;stry. Box 12-1,S-22100 Lllnd. Sweden: AND FLEMMING

HEGELUND. Univers;ty o[ Arhlls. Department o[ Chem;stry.

Langelandjgade 140. DK-8000 Aarhus. Denmarlc.

A storagc ring acts as an approximate point source in thc far-infÌ"ared with a

much greater intensity than traditional thermal sources. This method has the potential

for greatly improved signal-to-noise ratios in high-resolution spectra at wavenumbers

below -1000 cm'l. provided that problems related to the pulsed nature of the source and

electron beam motions can be overcome: The utility ofthe storage ring combined with

a Bruker HR-120 FTIR will be iIIustratedby severa1examples.includingHCI04, IBr.~

and IC1. In the case of perch10ricacid (HCI04). approximate1y1100 transitions in

H3SCI04and ca. 300 in H31CI04have been fitted using single subband analysis.

gcnerating constants for transitions having the same K.< The origin of the H3SC104 K =

3t serics is found to be 726.9971(4) cm-I.

'Johnson. M. S. and B. Nelander. High-resolutiongas phase spectroscopy with a

synchrotron radiation source, NIlOvo Cimento D. in press.

"Nelander. B., V. Sablinskas. M. Dulick. V. Braun. and P. F. Bernath. High-resolution

far-infTared spectroscopy of IBr using a synchrotron source. Mo/. Phys., 93( 1).

137 (1998).

<Johnson. M. S.. F. Hclgelund. and B. Nelander. The V5band ofperchloric acid. J. Mo/

Spec.. in press.

POSTER SESSION.N47

THE MICROW AVE SPECTRUM OF M-CRESOL

A.HELLWEG andW.STAlll..

Institutjùr Physikalische Chemie, RwrH Aachen

Templergraben 59

52056 Aachen, Germany

he[11~'eg@miro.pc.n~1h-aachen.de

The microwave spectrum of m-cresol (3-methyl-phenol) has been recorded

between 3 and 25 GHz using a pulsed beam Fourier transfo~ microwave

spectrometer.

The tunne1ing of the OH group in two unequal minima leads to different spectra

for the cis- and the trans-conformer. Due to the intemal rotation of the methyl group

the transitions ofthese conformers are split. The A state 1inesfor both conformers have

been observed and assigned. The rotational constants and the centrifugal distonion

coefficients were determined.

The torsional splittings (presumably 0.1 to 10 GHz) of the low threefold barriers

hindering intemal rotation of the methyl tops are currently under investigation.

POSTER SESSION,N48

DYNAMICS STUDY ON HYDROGEN AND MUONIUM ATOMS TRAPPED IN

DIAMOND CRYST AL AT FINITE TEMPERA TURE

A .SHIMIZU 1, H TACHlKAWA 2 and M INAGAKI1

I Hokkaido UIIÎI'ersily, Division 0/ Malerial Science, Gradllale School 0/ ElIgilleering

2 Hokkaido UlIil'l!rsily, DMsioll 0/ Moleclllar Chemislry, Gradllale School 0/

ElIgilleerillg

Kifa-kll, Sapporo 060-8628, Japall

Electronic state and transport process of the atoms trapped in the solid are important

subject in relalion to atomic diffusionand defect structure in the bulk In the present

study, concerninghydrogenand normal muoniumatoms trapped in the diamond lattice,

we investigatedthe electronicstates and the transport mechanismof these atoms on thebasis of semi-empiricalPM3 MO method combinedwith the direcl dynamicscalculation.

Normal nuomiumis an isotope of hydrogen atom whose mass is one ninlh of that of

hydrogen. We havegot some information'son the behavioroftrapped alom at certain

temperatures which have not been obtained by the convenlionaltheoretical treatment.

The struclures of four clusler models val)'ing Ihe carbon numbers from ]4 1026 were

oplimized before and after trapping of one hydrogen atom inside of the lattice.Calculationof spin density (0 977 at OK)and its dislributionsuggest that the atom is

trapped at the letrahedral site and that the eleclron of hydrogenatom is transferred to

carbon aloms. The frequenciesof hydrogen and muoniumIrappcd in the cluster give

three strong speclra ranging from 23147 to 2345.1cm"1and 6788.8 to 6840.5 cm-I,

respectivelywhich mean Ihat these atoms are deeplytrapped and show the frequencies

dependent upon their mass numbers Next, thermal fluctuationswere obtained in the

temperature range of 4 to l000K for the potential energy undergone by the trapping

atom and for the two distances between trapping atom and two nearest host carbon

aloms and for the angle among Ihesethree aloms 80th hydrogenand muoniumatomsshow the increase in Ihose Ihermal fluctuations with the increase of simulation

temperature, however, the latter shows the highervalues in amplitudeand frequencyof

the vibrations at the given temperatures due to Ihe smaller mass number From the

examinationofthe frequency,the vibrationalmodecouplingis consideredto occur with

the lattice phonon mode As a result, spin density of trapping hydrogen is slightly

reduce to 0.975 at 300K. In the vel)' high temperature region (T>1500K),the lattice

vibration becomes slronger and the hydrogen atom altacks nearby carbon atoms,resuhing in the C-H bond fomlalion

POSTER SESSION,N49

THE MICROWAVE SPECTRUM OF 3-METHYL-BENZONITRILE:METHYL INTERNAL ROTATION AND 14N NUCLEARQUADRUPOLE COUPLING

T.BRUHNANDH.MÃDERInstitut !ür Physikalische Chemie, Universität Kiel, D-24098 Kiel, Ger-many.

The microwave spectrum of 3-methyl-benzonitrile, CH3C6H4CN, has becn investigatedin the range from about 2-4 and 8-20 GHz. The assignment of the spectra in the lwolowest slates of internal methyl rotation (m=O,I) was achieved by means of pulsed molec-ular beam Fourier transform microwave (MB-FTMW) spectrometers. Thus lines up toJ=l1 were measured and analysed together with further lines (,1>21) obta:ned witha waveguide FTMW-spectrometer, yielding rolational conslants A=3295.530(36) MHz,B=1199.051(1O) MHz, C=883.900(8) MHz, a threcfold barrier to inlernal rotalion of lhemethyl group of V3=402.80(8) GHz, and an angle between the internal rotor axis and thepricipal a-axis of 11=42.677(3)0. Analysis of the nitrogen nuclear quadrupole hyperfinestructure of the lines a\lowed to determine the coupling constants Xaa=-3.627(1) MHz,Xbb=1.684(1)MHz, Xcc=1.943(1) MHz, and Xab=-1.869(1)MHz, the latter being availablefrom the m=1 lines. Thus the principal elements of the x-tensor wilh ils z-axÌ8 longthe CN-bond axis could be determined to X..=-4.219(2) MHz, Xn=2.276(2) MHz, andX~~= Xcc=1.943(1) MHz.

POSTER SESSION, N50

NOT ALL ARE EQUAL - THE CARBON-CARBON-BONDS INCYCLOBUTADIENE-ffiONTRICARBONYL

O. INDRIS, W. STAHL, Inst. 01Physical Chemistry, RWTH Aachen,Templergraben59, 52056 Aachen, Germany.

Cyclobutadiene is the simplest Hückel-antiaromat and therefore rather unstable. One way00 stabilize this molecule is 00 build a complex where the cyclobutadiene is coordinated00 a central metal aOOm via 1I"-honds.

It is now interesting whether the structure of the cyclobutadiene in this complex is a rectan-gle or a perfect square. Electron diffraction studies could give no answer to this question1,

as the difference in the carbon-carbon-bonds is 000 small. Earlier microwave investigationsdescribed this molecule as a symmetric OOp2.3,probably due 00 a lack of resolution. The

reinvestigation of the rotational spectrum by FT-MW-spectroscopy in a molecular beamrevealed additionallioes, which Cormed a triplet Cor each J' +-J-transitioo. We propose an

ioterpretatioo oC this spectrum by a model oC an asymmetric cyclobutadieoe-frame 00 a

Fe(COh-roOOr which perCorms an almost free ioternal rotatioo.

1. M.I. Davis, and C.S. Speed, J. Organometal. Chem., 21, 401-413, (1970).2. E.A.C. Luckeo, R. Pozzi, and K.R. Ramaprasad, J. Mol. Struct., 18, 377-380, (1973).3. M.A. Rohrig, P. Wikreot, S.R. Huber,'D.E. Wigley, and S.G. Kukolich, J. Mol. Spec-trosc., 154, 355-360, (1992).

POSTER SESSION, N51

Collisional broadening of two millimeter-wa\'c

transitions of HCN and HC3N

perturbed by N2. H2. and He.

Jean-!\'Iarcel Colmont. Pascal Dréan. Dominiquc Priem.

François Rohart. and Geor~es Wlodarczak.

Laboratoire de Physique des L1sers. Atomes et Molécules. UMR CNRS.

Bât P5. Université des Sciences et Technologies dc Lille

59655 Villeneuve d'Ascq Cedex. France.

The knowledge of thc lineshapes is necessary to a proper analysis

of the absorption figures recorded from ground-based facilities 01' from

satellite plateforms. It is well known thal Ihe collisional broadening

coefficien\s and their temperalure dependence play an important role in the

profiles of the lines.

In connection with Ihe past 01' planned exploration of the

atmospheres of the gianl planets. measurements of collisional broadenings of

Ihe J=3--2 line of HCI5N located al 258 GHz. and the J=24--23 line of

HC314N located al 218 GHz. have been carried OUIin the temperature range

235-350 K. The major componanls of Ihese planet's atmospheres: N2. H2.

and He have been considered as perturbers.

The foreign broadening coeftïcienls and their temperature

dependence paramelers werc determincd assuming a Voigt profile and the

I1sual power law for Ihe tcmperalUre dependence of the collisional broadening

coefficienls.

ln view to poinl nut a possible Dicke narrowing effect. the experi-

menlal figures were also compared 10 a Galatry profile.

We present here Ihe firsl resulls on the broadening coefficien\s of

Ihese two nitriles. and the most appropriate profiles for describing the

experimental lineshapes. The relrieved values are compared to Ihe values

calculaled using the semi-classical formalism of Anderson and to the values

obtained from previous invesligations.

')011

POSTER SESSION. N52

New observations and new analyses

in the spectrum of the 12C160+ ion molecule

R,K~pa, A.Kocan, I.Piotrowska-Domagala, M.Rytel and M.Zachwieja

Alomic and Molfcular Physics Laboralory. Jnstilule 01 Physics, Ptdagogical ['nil'fr-sily. PL-.]5-31O R=fs.:ÓII',Poland

In the emission spectrum of the 12C160+ -ion molecule new registrations andne\\' ana\yses of the bands belonging to three main band systems: B2~+ - X2 ~+,B2~+ - A2n and A2n - X2~+ have been made. Under high resolution and by meansof the conventional photographic spectroscopy 19 bands comprising 3 bands of theß - X system. S bands of the 8 - A and 8 bands of the A - X systems with totalnllmber of abollt 4;00 lines have been recorcled. Estimated precisiol1 of the singlelines is cOl1sidered to be in the range 0.005 - 0.010 cm-1. The fìUing of the spectraand the ca\culatiol1 of the ro\'ibronic structure parameters of the 8, A and X states\\"ere performecl directly. with the effective Hamiltonians of Brown el al. (1). In thismethod, based on a nonlinear least-squares procedure each of band in a preliminarystep of analysis was fìtted individually and tested for the number of indispensableconstants. Considering the precision of the obser\'ed wavenumbers of the lines andthe highest observed J vallle is only J = 38.5 the followingparameters: B.. D., and1. for the B2~+ and X2~+ states and: B.. D.. A., AD., P. and q. - for the A2nstate. as \\"1"11as /lo-values were statistically signifìcal1L

The fìnal moleclllar constants were calclllated from the merging of the resu\tscomputed from all il1dividllal fìts. These moleclllar constants were then used to calcu-\ate and to perform a ne\\" spectroscopic al1d qual1tllm-mechanical characterizationof the X2~+, A2n and B2~+ electronic states in the 12C160+ iOI1molecule (2,3).

..................................................................................

1. J.l\I.BRO\\'i\. E.A.CßI.BOliRI'\, J.K.G.WATSOl'i Ai\'D F.D.WAYNE.

.J.Mol"'IJfrl/'osc.. 74. 29.[.318 (19;9).

2. K.P.HIOER A~D G.HERZBEIIG. Molfcula/' Spfcl/'a and .\Iolecular SI/'uclurt/1'. ('011$1(11I1.<01 Dialomic Moltcu/ts (N.Y. Van Nostrancl Reinhold).

:3. C .HARIDASS. C. \'. \'. PRASAD. 5.P .REDDY. A$ll'OphY$. J.. 388. 669-6;; (1992).

POSTER SESSION.N53

DIPOLE MOMENT FUNCTION OF LIF AND LICL OBTAINED FROM THE

HERMAN-WALLIS ANALYSIS: A COMPARATIVE STUDY WITH THE

MBERDATA

EJIQ, P. KLOSE", T. NAKANAGA, H. TAKEO' AND H. JONES"

Nationallnstitute o[ Materials and Chemical Research. Tsukllba, Japan.

'Nationallnstitllte [or Advanced Interdisciplinary Research. 1:~ukuba.Japan.

"Abtei!lIng Chemische Physik. Universität U/m. Ulm. Germany.

We have reported the results ofthe Herman-Wallisanalysesof diatomic metal hydrides

AIH, GaH' and InHb,to get the information on the dipole moment function (DMF) of

each molecule. Since there is no other experimentaldata, we were not able to discuss

the reliability of the DMF thus obtained. To estimate such accuracy in intensity

analyses, it is the best way to compare the result of the analysis with that of more

precise methods like molecular-beam electric resonance (MBER) or laser-Start

spectroscopy.

In this paper we will present comparative studies of the Herman-Wallis analysis with

the MBER study for LiF and LiCI. V-dependent permanent dipole moment has been

measured for each molecule by Klemperer's group more than twenty years ago with the

MBER technique. Reanalysis of the data (by perturbation or variational treatment)

gave us the DMF of each molecule, which were compared with the results of the

intensity analyses of FTIR spectrum of each molecule measured in Tsukuba. The

comparison showed us that they agree with each other within 15% or so. 11means that

the Herman-Wallis analysis can give relatively reliable DMF, although its accuracy is

still .one-digit' .

'F. Ito, T. Nakanaga, H. Takeo and H. Jones, J. Mol. Spectrosc., 164, 379 (1994).

~. Ito, T. Nakanaga, H. Takeo, K. Essig and H. Jones, ibid., 169,421 (1995).

POSTER SESSION,N54

I\IODELLlNG SPECTRA OF SPECIES IN I\IOLECULAR I\IATRICES

A V.NEtl.IUKHIN,B L GRIGORENKO. N \' OZHEGOVA. A YU ERMILO\',

AND \\' E KLOTZBUECHER.

( ï"!lI/isll:r 1kpClrlll/elll. A!()SCUII Slal<' UII"'l'rsi~r. ^ {()SC()W, 1/9899 I?II.uia.

.\ lax-I'lallck-llIsllllllfllcr Slrah!ellcl1ell/ie. 1 )-./5./ 70 AIlIell1eill/ RIII1r. GermGIIY

Thc c\al11plcs of 1110ddling spectra of specics trapped by 1110lecular l11atrices by means

of quantul11 chcl11istry approachcs are considcred Such 1110delling prelends for

interpretations of the e\peril11ents with cryogenic matrices of molecular origin Ab

initio approachcs wilhin the cf1ectivc core potential (pseudopotential) rcpresentations

arc applied tl.lolccular clusters describing fragmcnts ofthe rnatrices with the cl11bedded

spccies arc selected for analysis and features In either \'ibralional or electronic spectra

art' rcproduccd Thc optical spcctra of the holmilll11 carbonyls forl11ed in thc CO

l11atrices upon irradia!lon 01' the cocondensation prodllcts are sil11111atcd.The pril11ary

targct is thc HO(CO)6 complc\ althollgh othcr cOl11posi!lons are takcn into

considera!lon as \\ell Anolhcr systel11s l110del thl' liqllld Cf\ stal (c\'anobiphenyl) traps

111rthe silver panicles The tì'agl11ents of cyanobiphenyll11olecul('s form thc cages for

silver. and calclllations of the shifts of vibrational bands attributed to the CN grollps of

the l11atri\ l11atcrial dllc to interactions with the l11etal the pro\'ide an imerpretalion of

thc e\perimcmal rcsults

POSTER SESSION.N55

SPECTRAL CHARACTERISTICS OF NON-HOMOGENEOUS SOLUTIONSNEAR THE EXFOLIATION CRITICAL TEMPERATURE.

A D ALEKHIN. S.G.OSTAPCHENKO. D.B.SHVIDKA. D.I.MALARENKO

Taras Shevchenko Kyiv Uniwrsiry. physics c/epartmenlG/ushkom 0\'('.6.252022 Kyil'. Ukraille.

Equilibrium and kinetic properties of binary solution cssentially change along th.:altitude in the vicinity of the exfoliation critical temperature due to limitless incr.:ase 01'system susceptibility under gravity.

In the present work the altitude and temperature dependencies_ of li~ht scatteringintegral intensity I(z.t) as well as half width 01'Rayleigh ccntrallinc A=Dq- was studicdin inhomogeneous double solution isooil acid-hcavy watcr in the \'icinity 01' thcexfoliation critical temperature. The diffusion coeOicient D(t) temperature dcpcndenccalong critical isochore (t=(T -TcYfc >0) and phase intcrfacc (t<O) as wcll as thc ficlddependence D(z)-À(z) on inhomogeneous system altitude at solution criticaltemperature Tc were investigated on the basis of obtained data.

POSTER SESSION,N56

THE SPECTROSCOPY OF WATER COMPLEXES.

N. ZVEREV A

Siberial1 Physical-Techmcolll1.5titllte, Nom-Sohomaja sq.I, 63-1050, Tomsk, R/lssia.

The present study considered the structural and spectral trends in water complexes

(H20)., , n = 2 - 7 HF calculations have been done Two types ofOH bonds are present

in water complexes. a bridge OH bond that participates in the hydrogen bonding and a

free OH bond that is oriented above or below the (000) plane. The lengths ofthe bridge

OH bonds increase monotonically with the increasing complex size. There is little

change in the lengths of the ftee OH bonds The vibrational spectra of water complexes

show a blue shift in intermolecular bonds with respect to monomer and red shifts in the

OH stretches, these results in a good agreement with experimental observations for

small water complexes as well asbulk water

POSTER SESSION.N57

PURELY ELECTRONIC ZERO-PHONON LINES AND SINGLEIMPURITY MOLECULE SPECTROSCOPY

I:'-iNA K. REBANE A:'\D KARL K. REBANE. lnstitutc 01 Physir.-.Univ(rsity 01 Tar.tu. Riia 142. EE2400 Tnrtll, Esto"in

Purely electrollic zcro-pholloll lillc (ZPL) - thc optical analog of thl' Î-rCSOllaIlCl' ~Iöss-

bauer line - is a rcmarkable fcature of the lo\\' telllpcrature vibronk spcclra of illlPllrityactivatcd solids. ZPL is thc foundation 5tOllC of thrcc novel l1Iethods: high rC50lulion

spectroscopy of molcculcs and othcr dcfects isolatcd in solid malriccs. pcrsislpnt spl'ctralhole burning. singlc impurily rnoll'culc (impurity Cl'nlrc) spl'ctroscopy (S~IS) (5l'c1.2 and

rcferenccs thcrcin).1'he latter is owing to thc lIarrOWnl'SS (~ 1O-3-1O-5crn-l) and high pl'ak absorplioll cross

section (- 1O-lIcm2) of ZPL very sClIsitivc both spatially alld ill tlw frcqu('n('y dOlllaill.Theorctical considNations supportcd by cxpcrimcntal spcctra for lcrrylcnc ill n-dccalll' (a

Shpolsky systcm3) show that Si\IS is not mcrcly a vcrsioll of the con\'Plllional spcctroscopydcveIoped up 10 t he accuracy ncccssary to mea5ure sillglc impurity molccull'5. hUl has quitra few specifìc featurcs. absent 01' negligiblc in thc conventional spect roscopy.

Rclaxation of lhe lIoll-cquilihriulII ellergy (mechanical. clectrkal ctc.) ston'd in lhc salllplc.

after it is coolcd to liquid hclilllll tempcraturcs is thl' long-lasting drivillg fOITl' for ('hallgingits structure. 1'hc latter causr5 til1l('-depcndcnt challgc.s of thl' illhoJ1)ogell('ous stru('IIJrl'

and, consccjuelltly. ill thr S~IS spcctra. ßccausp of the vcry high sC'lIsiti\'ity or S~!S.various challgcs call hr reliably mca5urcd (as pxamplcs cxperillll'lItal data 011tCI'I')'lrlle

in n-dccane alld pClltaccllc ill paratcrphcllyl).Thc followillg qucstiolls arc cOlIsidcrcd:

i. Positions and shaprs of ZPL ill thc cOllditions of til1lf'-dc'pclldclIl illhol1logf'lI(,ous struc-

turc of thf' sal1lplf'.ii. I'cak absorption rross-scclion of thc ZPL takillj!; inlo a('('Q1I1I1thf' pholloll sidf' halld of

ZPL and the hroadellinJ1; causcd by timc depcndcncc of thf' illhomogcllcity of thf' salllplr.iii. J)cfìnition or thc ..homol!;f'lIcoUS ZPL" as thf' ZPL of a sillglc lIIolcculc. l1If'asUrl'd durilll!;

a propcr tilllc intcrvaLiv. Comparisoll of single lIIoll'('ulc spcctroscopy alld singll' lIIoll'culc dctc!'lioll.\'. ProSpl'Ct5 of tlu' appli('ations of S~IS a.s a sclcclivc and sl'lIsili\'f' prohc or solid IIlal1N.

Potcnlial applkations in D\A scquencillg.

1. K. K. Hchallc. J. ChclII. I'hY5.. 189, 139 (199.1).

2.1". K. Rchanr..1. ~Iolf'cular Slruclurc. 347. 3.~1 (1995).

3. O. Ollikair1C'lI, \'. Palrn. alld K. K. Itcbane, OptÎ('s all(l Spe('troscopy (St. I"'lersburg).10 be publisl1C'd.

POSTER SESSION, N58

STRUCTURE AND SPECTRA OF 1\IOLECULAR COMPLEXES WITH THE

DIATOl\IICS-IN-MOLECULES POTENTIAL ENERGY SURFACES

B.L.GRIGORENKO AND AV.NEMUKHIN

Chenllstry Departmel/t. MosC()1\' State Ulliversity. Mosco\l'. 119899 RlIssia

The diatomics-in-molecules (DlM) theory allows one to create the potential energy

surfaces particularly suitable for applications in molecular dynamics simulations of

structure and spectra of intermolecular complexes since an evaluation of the energy

and the energy derivatives is not an expensive procedure with this technique. We are

developing a systematic approach to construction of potential functions of the van der

Waals clusters based on the balanced treatment of the neutral and ion-pair

contributions within the DIM scheme. The diatomic potential curves are either

borrowcd from the experimental data or computed with the ab initio quantum

chemistry methods. Successful attempts to create the potential energy surfaces of the

spectrJscopic accuracy for the Ch Rg (Rg = He, Ne. Ar)" and SH. .Kr complexes in

the excited electronic states as well as for hydrogen fluoride dimer (HF}z in the pure

stateb and trapped by the argon clusters< will be presented.

'B L Grigorenko, AYNemukhin and V AApkarian, Chem.Phys. 219, 161-172

(1997)

bB L Grigorenko, AV Nemukhin and VAApkarian, J.ChemPhys. 108,4413-4425

( 1998).

<B L.Grigorenko and A V Nemukhin. Chem.PhysLett. 270,103-107 (1997)

POSTER SESSION,N59

08SERVED ENERGY LEVELS OF I1CI602 DERIVED FROM THE RITZ PRINCIPLE

S.A.TASHKUN, V.I.PEREVALOV.

Jl1slilllle of Almospheric Oplics. Siberial1 Bral1ch.

RlI.uial1 Academy ofSCÎences.J. Akademicheskii (/1',. 63-1055 Tomsk. RlI.uia

D.BAILLY N) J.-L.TEFFO

LaboralOire de Physiqlle MoléclIlaire er ApplicaliollS, C.N.R.S.,(Laboraroire associé OlL\'Vlliversilés Pierre er Marie Curie el Paris-SlldJ,

Vlliversité Pierre et Marie Cllrie, Boite 76,4 Place JlIssiell, 75252 Paris Cedex 05, Frallce

Using the fundamental Ritz principle 5202 energy levels of 12CI602 Iyingbetween 0 and 27000 cn,.1 have been derived from the 1east-sql1ares fit of 11575

observed line positions. The root mean square of the fit is 2.4 x 10-4cm,l. The standarderrors of the energies vary from 7.0 x 10'5 cm'/ to 2.1 x 10'3 cm,l. The calibration offsetsof Fourier Transform (FT) spectra involved into inpl1tdata relative to the high precisionlaser helerodyne (LH) l11eaSl1rel11entsare also deterl11ined, The observed data are takenfrol11the literalure and extended with original FT l1ame emission spectra meaSl1n:ments,The tile 01'Ihe input data includes 6 LH spectra and 31 FT spectra.

1'0 take into account the possible systematic frequency offsets for the F1'measurel11cnts relati\'c to LH reference lines the Ritz principle has been lIscd accordingto the following equation

v~., = E, -E, +8"

where \". is the wa\'enumbcr eXIr.tcled frol11the k-th spectrLIl11.â, is Ihe calibralion

offscl lor Ihis spectrl1l11. E, and E are the encrgies of lo\\'er and l1pper stales.

respccti\'e1y. Here 6, is zcro if 1"_, originatcs from thc LH l11easurements and ð, is an

l1nknown qllantity if I'~__originates from thc FT l11easuremcl1!s.Sincc the nllmber of thc

obser\'ed transitions ,\', is greater than the number 01' l1nknown cncrgies i\'. pllls Ihenllmoer ,\,/ 01' the F1' spectra. it is possible 10 sol\o: thc o\'erdetcrmined system of .\,linear eqllalions wilh ;\"" - -"n unknown quantitics in the leasl-sqllarcs sensc, Theprincipal ad\'antage 01'this approach is that the reslllting sel 01'N. -1 encrgies (Ihc 10\\eslenergy ha\ing zero \'alue) does not depend on any Hamiltonian model. The otherad\'antagc of this approach is connected with the possibility to deri\'e a systematic olTselfor a FT spcctrl1m when directly measured reference lines are missing in the speclralregion 01'intcrest. 1'his approach gives also the possibility to detcct misassigned lines.

A sparse matrix technology has been used to sol\'e the system 01' ) )575 linearequations with 5233 unknO\vn quantities. AII ca1culations ha\'e been performed nn aPentium PC with 16Mb of RAM.

306

POSTER SESSION, N60

HANIFESTATION OF THE STRONG LIGHT HOLECULE INTE~TION

IN THE SURFACE ENHANCED OPTICAL EFFECTS

A. H. POLUBOUO

A.F. Ioffe Physico-Technical Institute Russian Academy of

Sciences, Politechnicheskaya 26 194021 Saint

Petersburg RUSSIA.

Fax: (812) 247-10-17, E-mail: Alex@marina.ioffe.rssl.ru

There is a series of optical effects, arising on

molecules, adsorbed on rough surfaces. They are SERS,

enhancement of infrared absorption and some others. In our

work it was demonstrated, that the reason of these effects

is a quadrupole light-molecule interaction, arising in

strongly heterogeneous surface fields. The theory

explaines why the surface enhanced processes arise in

rough systems, the nature of so-called active sites, the

short range enhancement or the first layer effect, the

long range enhancement and its height dependence, the

absence of polarization dependences for arbitrary rough

surfaces, the frequency dependence of SERS and some other

phenomena. Of special importance is possibility of

explanation of regularities of the enhanced spectra. The

theory demonstates that for symmetrical molecules and low

coverage of the substrate the most enhanced bands are

caused by totally'symmetric vibrations and by the ones,

transforming as the dz component of the dipole moment,which is perpendicular to the surface. Depending on the

symmetry group of the molecule there may appear lines, of

various intensity which are forbidden in the usual Raman

scattering. For the enhancement of infrared absorption

peculiarities of the enhanced spectra are very close. The

most enhanced bands are caused by the totally symmetric

vibrations and by those transforming as the dz moment.Besides the most enhanced band must be the one caused by

the breathing mode. These regularities are well observed

experimentally on a large number of symmetrical molecules.307

POSTER SESSION,N61

HIGH RESOLUTION ELECTRONIC SPECTROSCOPY OFTHE MgNC RADICAL: SPIN -ORBIT COUPLING ANDRENNER-TELLER INTERACTION IN THE Ã2n ELECTRONICSTATE

R. R. WRIGHT AND T. A. MILLER, Laser Spectroscopy Facility,Department 01 Chemistry, The Ohio State University, 120 West 18thAvenue, Columbus, OH 49210.

High resolution, rotationally resolved, laser induced ßuorescence (LIF) spectra for the

origin band, as well as several transitions involving vibrationally excited levels, of theÃ2n 4- X2E+ electronic transition of the MgNC radical have been recorded. The MgNCradical was generated in a supersonic free jet expansion by simu1taneous laser ablation of

a magnesium rod and photolysis of acetonitri1e (CH3CN). The radicals were probed bythe output of a pu1se-amplified Ti:Saphire ring laser. Rotational analysis yielded both the

ground and excited state molecular constants for the studied vibronic transitions. The

molecu1ar constants for the vibrationless state of the X state are in excellent agreement

with previous microwave studies of MgNC, which gives additional support for the identi-fication of the carrier of the spectra. Since the à electronic state of MgNC is a linear 2nstate, the bending vibronic level structure is subject to the Renner-Teller and spin-orbit

splittings, and 50 the vibronic assignments of the observed transitions, which are consistentwith the rotational analysis, are discussed in terms of these two interactions. Additionally,

two of these vibronic levels, the 2A2E+ and the 2ä 2n1/2 levels, interact with each other bymeans of a second-order perturbation of the product of the Renner-Teller and spin-orbithami1tonians, observed previously in the NCS radical.