20 june 200661 st international symposium on molecular spectroscopypetkie – tg03-p1 the millimeter...
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20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p11
The Millimeter and Submillimeter-wave Spectrum of the 8191, 6171, and 21 Vibrational States of Nitric
Acid
Douglas T. PetkieDepartment of Physics, Wright State University
Paul HelmingerDepartment of Physics, University of South Alabama
Ivan R. Medvedev, Atsuko Maeda, Frank C. De LuicaDepartment of Physics, Ohio State University
International Symposium on Molecular Spectroscopy61th Meeting
June 19-23, 2006The Ohio State University
Columbus, Ohio
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p22
Outline
• Introductory remarks and overview
• Experimental details and data
• Details of each state/analysis
– previous studies, current assignments and analyses
2 = 1
6 = 7 = 1 and 8 = 9 = 1
– Torsional splitting
• Summary
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p33
Nitric Acid Vibrational States
Review article “Recent progress in the analysis of HNO3 spectra” by A. Perrin, Spectrochimica Acta Part A 54 (1998) 375–393.
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p44
Nitric Acid Vibrational Levels
assignments and initial analyses
Published analyses
a = 1.98 D b = 0.88 D
a-type Ka = 0, 2 Kc = 1, 3
b-type Ka = 1, 3 Kc = 1, 3
N
O O
O
H
Current Focus
Current Focus
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p55
Interference fringes Spectrum
InSb detector 1
InSb detector 2
Ring cavity: L~15 m
Mylar beam splitter 1
Mylar beam splitter 2
High voltagepower supply
Slow wave structuresweeper
Aluminum cell: length 6 m; diameter 15 cm
Trigger channel /Triangular waveform channel
Sig
na
l ch
an
ne
l
BWO
Magnet
Lens
Filament voltagepower supply
Length ~60 cm
Steppermotor
Reference channel
Lens
Stainless steel rails
Path of microwaveradiation
Preamplifier
Fre
qu
en
cy
ro
ll-o
ffp
rea
mp
lifi
er
Referencegas cell
Glass rings used to suppress reflections
Data acquisition system
Computer
FAst Scan Submillimeter Spectroscopic Technique (FASSST) spectrometer
WI04:WI04: FAFAST ST SSCAN CAN SSUBMILLIMETER UBMILLIMETER SSPECTROSCOPIC PECTROSCOPIC TTECHNIQUE (FASSST). ECHNIQUE (FASSST).
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p66
FASSST Data• 118-375 GHz, Heated ~180 oC, Signal averaged data ~ time constant ~ 20 msec
• plus “legacy data” (78-118 GHz synthesizer and older FASSST data)
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p77
-800x103
-600
-400
-200
0
200
400
Sig
na
l/a.u
.
260x103
255250245240Frequency/GHz
R and Q Branches
FASSST Spectra
Simulation ofground state
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p88
4000
3000
2000
1000
0
-1000
-2000
106.6106.4106.2106.0105.8105.6x10
3
gs
32
Assignment Methodology
7080 78
106 GHz region
Frequency /GHz
Sig
nal/a
u
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p99
Relevant Studies of 2 = 1 2 High-resolution infrared studies (b-type transitions):
– Laser Diode:• C. H. Bair and P. Brockman, Appl. Opt. 18, 4152-4162 (1979)• A. G. Maki and J. S. Wells, J. Mol. Spectrosc. 82, 427-434 (1980)• A. Maki, J. Mol. Spectrosc. 127, 104-111 (1988)
– 15 MHz, 1680 – 1738 cm-1, J = 66, Ka = 35, Kc = 60– No perturbations:
» few low Ka do not fit: 1676-1683, 1731-1736 cm-1
– FTIR:• T.L. Tan, et al., J. Mol. Spectrosc. 155, 420-423 (1992)
– 15 MHz, J = 72, Ka = 45, Kc = 72– 1675-1684, 1730-1737 cm-1, Ka ≤ 7 (J~64)
» obs-calcmax = 245 MHz (0.0082 cm-1)» Severely overlapped, as with Maki» Excluded from analysis and not understood
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p1010
2 = 1 Assignments and Spectra
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p1111
R-Branch SummaryInfrared transitions obs-calc up to 245 MHz
R = Fitted TransitionRP = well predicted clear region, missing transitionRP? = well predicted but congested* = no spectra available
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p1212
Q-Branch SummaryInfrared transitions obs-calc up to 245 MHz
Q = Fitted TransitionQP = well predicted clear region, missing transitionQP? = well predicted but congested* = no spectra available
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p1313
2 = 1 Spectroscopic Parameters and Summary
• Starting point was Tan, et al. constant set
• Watson A-reduced Hamiltonian in the Ir representation
• 207 fitted transitions between
78-505 GHz• Maximum Quantum Numbers
J = 40, Ka = 19, Kc = 40
• 117 kHz rms deviation• Constants in fairly good
agreement with ir work• Possibility of perturbation• Spectral congestion
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p1414
96
72
98
76
Infrared Laboratory Spectrum
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p1515
Nitric Acid Vibrational Levels
assignments and initial analyses
Published analyses
a = 1.98 D b = 0.88 D
a-type Ka = 0, 2 Kc = 1, 3
b-type Ka = 1, 3 Kc = 1, 3
N
O O
O
H
Current Focus
Current Focus
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p1616
Previous Studies for8 + 9 and 6 + 7
• A. G. Maki, J. Mol. Spectrosc. 136, 105–108 (1989).– Infrared Spectrum of the 1205 cm-1 Band of HNO3
• T. M. Goyette and F. C. De Lucia, J. Mol. Spectrosc. 139, 241–243 (1990).– The millimeter and Submillimeter Wave Spectrum of the 8 + 9 State of HNO3
• W. F. Wang, P. P. Ong, T. L. Tan, E. C. Looi, and H. H. Teo, J. Mol. Spectrosc. 183, 407–413 (1997).
– Infrared Analysis of the Anharmonic Resonance between 8 + 9 and the Dark State 6 + 7 of HNO3
• A. Perrin, J.-M. Flaud F. Keller, A. Goldman, R. D. Blatherwick, F. J. Murcray, and C. P. Rinsland, J. Mol. Spectrosc., 194, 113–123 (1999).
– Analysis of the 8 + 9 Band of HNO3, Line Positions and Intensities, and Resonances Involving the v6 = v7 = 1 Dark State
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p1717
500x103
400
300
200
100
0
-100
-200
Sig
na
l/a.u
.
220.0x103
219.5219.0218.5218.0217.5217.0Frequency/GHz
8000
4000
0
-4000
6171 and 8191 Assignments and Spectra
Predicted SpectraX50 vertical scale
FASSST Spectra
6171 8191
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p1818
15x103
10
5
0
-5
-10
Sig
na
l/a.u
.
218.04x103
218.02218.00217.98217.96217.94217.92217.90Frequency/GHz
6=7=1 Assignments and Spectra
R-Branch “Triplets”
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p1919
Torsional Effects on the Spectrum
J+10,J+1
J+11,J+1
J+11,J+1
J+10,J+1
J0,J
J1,J
J1,J
J0,J
a-type b-type
R-Branch
o
0.6
0.4
0.2
0.0
-0.2
315.98315.96315.94315.92x10
3
b-type
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p2020
Torsional Splitting SummaryState Observed
Splitting in MHz
9 2.34
5 35.43
9 50.80
7+9 12.26
6+9 22.76
7 Not resolved
8+9 3.35
6+7 1.48
9 1746.83
6 0.75
4 4.03
3 3.88
7+8 2.26
7191 Triplet
b ba
316 GHz region
40
20
0
-20
Sig
na
l (A
U)
315980315960315940315920Frequency (MHz)Frequency/MHz
Sig
nal/a
u
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p2121
IAS Hamiltonian: 6171 and 8191 States• IAS (Internal Axis System) Hamiltonian
– SPFIT, SPCAT (Pickett /JPL)
• IR representation in the A-reduction (z = a, x = b, y = c)
• Interaction terms– Fermi and c-type Coriolis terms
termsaldistortionorderhigher
KEJJJJDCJBJAJH abbaabcbavv
)cos(222
abbaab
cbaKJovv
JJJJC
JJFJFJFFH 2222 2
2aK
framerotor
rotor
II
I
J+10,J+1
J+11,J+1J+11,J+1
J0,J
J1,JJ1,J
J0,J
a-type b-type
R-Branch
ob-type
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p2222
• General
– H. M. Pickett, J. Chem. Phys. 107, 6732 (2001)
– Hougen, J. Mol. Spectrosc. 114, 395 (1985)
• HNO3
– A. Perrin, J. Orphal, J.-M. Flaud, S. Klee, G. Mellau, H. Mäder, D. Walbrodt, M. Winnewisser, J. Mol. Spectrosc. 228 375 (2004)
– D. T. Petkie, T. M. Goyette, P. Helminger, H. M. Pickett, and F. C. De Lucia, J. Mol. Spectrosc. 208, 121 (2001)
– Coudert and Perrin, J. Mol. Spec. 172, 352 (1995)
Details of Torsional Models
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p2323
-2000
-1500
-1000
-500
0
500
1000
Sig
na
l
104.480x103
104.475104.470Frequency/GHz
“Quad” transitions• Torsional Splitting ~ Asymmetry Splitting
– Torsional State Interactions (Dab terms) between Ka even odd
• Near equal intensities
6171: 14d,8 – 14d
9
Simulated
FASSST data
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p2424
Range of Data SetJmax = Kc,max ~ 41Ka, max ~ 23rms ~ 400 kHz# transitions ~ 1000
Center of Fermi Interaction
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p2525
Comments on the Analysis• Each state has it own torsional splitting parameter
– The “Fo” term is fixed to zero
• Torsional splitting suggests a 70/30 % mixing of the wavefunctions
– Assuming an isolated interaction
• Fermi term agrees with with Perrin, et al. and Wang, et al• Currently no need for a Coriolis interaction term• Distortional constants are well-behaved
– JK and K tend to become correlated in IAS models for HNO3 and higher in magnitude than expected (order of magnitude)
• Message data and assignments to finish the analysis– Quad transitions
• Add the infrared data from Perrin, et al. and Wang, et al. for 8+9
– Jmax = 74, Ka,max = 48
– check how well the ir data is predicted from the mw measurements
– Fit for Fo
20 June 200620 June 2006 6161stst International Symposium on Molecular Spectroscopy International Symposium on Molecular Spectroscopy Petkie – TG03-pPetkie – TG03-p2626
Conclusions
• The pure rotational spectrum of 6171, 8191, and 21 excited vibrational states are well measured and characterized mm/submm wave region
• The stage is set for continued assignments and analysis of the set of ~6 states around 1300 cm-1