A precise study of the rotational spectrum of formaldehyde H212C17O and H213C17O

The pure rotational spectra of H₂¹²C¹⁷O and H₂¹³C¹⁷O have been investigated in the frequency region between 8 and 360 GHz in the ground vibrational state. For both isotopic species the ¹⁷O nuclear quadrupole coupling constants and spin-rotation constants have been obtained. From both Q- and R-branch transitions a set of rotational constants and several distortion constants could be derived employing Watson's formalism in A reduction. The obtained rotational constants are in Megahertz:

     

2.

Stark spectroscopy with the CO laser: The ν₂ fundamentals of H₂CO and D₂CO     

J.W.C. Johns  A.R.W. McKellar 《Journal of Molecular Spectroscopy》1973,48(2):354-371

The ν₂ (CO stretching) vibration-rotation bands of H₂CO and D₂CO near 5.8 μm have been studied using the technique of laser Stark spectroscopy. The following vibrational and rotational constants have been determined:

	H212C17O	H213C17O
$\text{A}$	281 965.0 (30)	281 987.3 (19)
$\text{B}$	37 812.287(45)	36 776.790(25)
$\text{C}$	33 214.523(31)	32 412.920(19)

     

3.

The absorption spectrum of the Ag₂ molecule     

C.M Brown  M.L Ginter 《Journal of Molecular Spectroscopy》1978,69(1):25-36

The high dispersion absorption spectrum of the Ag₂ molecule has been photographed in the ～5300–1500-Å region. Observations include the previously reported A ← X, B ← X, C ← X, D ← X, and E ← X transitions and a new H ← X transition which occurs in the vacuum ultraviolet. Extensive spectral blending precluded detailed rotational analyses, but the band structures are consistent with $\text{ΔΩ}\text{= 0}$ and $\text{ΔΩ}\text{≥1}$ for D-X and C-X, respectively. The H state is perturbed and probably predissociated. The following molecular constants (in cm^?1) were obtained from fitting bandhead data to the usual expressions:

Constant	H2CO	D2CO	Unit
$\text{ν}{}_0$	1746.011	1701.620	cm?1
$\text{A′}$	281807.8 ± 6.	141696.6 ± 7.	MHz
$\text{B′}$	38608.7 ± 5.	32068.4 ± 7.	MHz
$\text{C′}$	33738.7 ± 3.	25998.6 ± 10.	MHz
μ″	2.328 ± 0.006	2.344 ± 0.006	Debye
μ′	2.344 ± 0.006	2.364 ± 0.005	Debye

     

4.

Laser Stark spectroscopy in the 10 μm region: The ν₃ bands of CH₃F     

S.M. Freund  G. Duxbury  M. Römheld  J.T. Tiedje  T. Oka 《Journal of Molecular Spectroscopy》1974,52(1):38-57

Laser Stark spectroscopy of the ν₃ band of CH₃F has been carried out using coincidences with the 9.4 μm band CO₂ laser lines. About 350 Stark resonances were measured for the ν₃ fundamental bands of ¹²CH₃F and ¹³CH₃F. About 30 of them were measured by using a Stark-Lamb dip technique to increase the resolution and the accuracy of the data. These Stark resonances, together with the recent results of infrared-microwave two-photon Lamb dip measurements, were analyzed to give the following vibration-rotation parameters and the dipole moments in the ν₃ state,

State	Te	ωc	Xωt
X	0.0	192.0	0.58
B	35 838.6	151.8	0.87
C	37 631.6	171.0	0.84
D	39 014.5	168.2	1.20
E	40 159.9	146.1	1.58
H	58 273.1	165.9	2.46

     

5.

Acoustical measurement of solid state non-linearity: Application to CsCdF₃ and KZnF₃     

M.A. Breazeale  J. Philip  A. Zarembowitch  M. Fischer  Y. Gesland 《Journal of sound and vibration》1983,88(1):133-140

Combination of the results of two sets of measurements on the same crystalline samples of CsCdF₃ and KZnF₃ has made possible the evaluation of the third-order elastic (TOE) constants of these two fluoroperovskites. In the first technique the hydrostatic pressure dependence of the velocity of ultrasonic waves of different propagation and polarization directions has been measured to determine three linear combinations of TOE constants. In the second technique the fundamental and the second harmonic amplitudes of an initially sinusoidal longitudinal ultrasonic wave of finite amplitude propagating along the principal directions have been measured to determine three other linear combinations. Combination of the two sets of data leads to the following room temperature values of the TOE constants (in units of 10¹² dynes/cm²):

	12CH3F	13CH3F
$\text{ν}{}_0$	1048.610767 (62)	1027.493191 (69)	cm?1
$\text{B}$	25197.57 ± 0.03	24542.07 ± 0.43	MHz
$\text{A - A}{}_0$	?294.09 ± 0.60	?288.81 ± 0.37	MHz
$\text{D}{}_{\mathrm{J}}$	55.5 ± 1.2	56 ± 12	kHz
$\text{D}{}_{\mathrm{JK}}$	575 ± 63	464 ± 24	kHz
μ	1.9054 ± 0.0006	1.9039 ± 0.0006	$\text{D}$

     

6.

The 10.4 μm CO₂ laser Stark spectra of the ν₄ and the ν₉ bands of 1,1 difluoroethylene     

G Duxbury  H Herman 《Journal of Molecular Spectroscopy》1978,73(3):444-461

The ν₄ and the ν₉ bands of CF₂CH₂ have been studied using coincidences with the 10.4 μm band of the CO₂ laser and the 10.9 μm band of the N₂O laser. These resonances have been analyzed, together with recent microwave results, to give the following vibration-rotation parameters and dipole moments in the ν₄ and ν₉ states

Sample	C111	C112	C114	C166	C123	C456
CsCdF3	?13·2	?4·55	?3·12	?0·69	+2·6	?3·8
KZnF3	?16·6	?4·75	?0·52	?1·79	+3·2	?6·87

     

7.

The ν₃ fundamental band of HDCO     

J.W.C Johns  A.R.W McKellar 《Journal of Molecular Spectroscopy》1977,64(2):327-339

The ν₃ fundamental band (CO stretch) of HDCO at 1724 cm^?1 has been studied using both conventional infrared absorption and CO laser Stark spectroscopy. In addition to the excited-state (v₃ = 1) rotational constants, improved constants for the ground state of HDCO have been obtained by combining previous microwave data with some infrared combination differences. The following constants were determined:

	$\text{ν}{}_4$ CF2CH2	$\text{ν}{}_9$ CF2CH2
$\text{ν}{}_0$	925.7692 (2)	953.8057 (2)	cm?1
$\text{A}$	10 971.99 (2)	11 026.918 (6)	MHz
$\text{B}$	10 414.98 (2)	10 436.381 (6)	MHz
$\text{C}$	5328.48 (2)	5346.100 (6)	MHz
μ	1.382 (1)	1.382 (1)	D
$\text{μ - μ}{}_0$	0.014 (2)	0.004 (1)	D

     

8.

CO₂ and N₂O laser Stark spectroscopy of the ν₁ band of the ClO₂ radical     

Keiichi Tanaka  Takehiko Tanaka 《Journal of Molecular Spectroscopy》1983,98(2):425-452

The ν₁ fundamental band of the ClO₂ radical has been studied by means of the 10.6-μm CO₂ and N₂O laser Stark spectroscopy. More than 250 and 150 Stark resonances were assigned for the ³⁵ClO₂ and ³⁷ClO₂ species, respectively, and were analyzed together with the recent microwave and laser-microwave double resonance results to give molecular constants including spin-rotation interaction constants. The ν₁ band origins and electric dipole moments both in the ground and ν₁ states were determined accurately

Constant	Ground state	$\text{v}{}_3\text{= 1}$ state	Units
$\text{ν}{}_0$		1724.267	cm?1
$\text{A}$	198 119.75	198 210.4	MHz
$\text{B}$	34 910.646	34 676.6	MHz
$\text{C}$	29 561.488	29 331.3	MHz
$\text{μ}{}_{\mathrm{a}}$	2.3302	2.3486	D
$\text{μ}{}_{\mathrm{b}}$	0.195	0.190	D

     

9.

High-resolution Fourier transform spectroscopy of the ν2 and ν3 fundamentals of nitrosyl fluoride,FNO     

S.C. Foster  J.W.C. Johns 《Journal of Molecular Spectroscopy》1984,103(1):176-186

The ν₂ and ν₃ fundamentals of FNO have been recorded with a Fourier transform spectrophotometer at an apodized resolution of approximately 0.004 cm^?1. The Fourier infrared data have been analyzed together with previous microwave data to yield improved molecular parameters for the (000) and (010) vibrational states and the first set of constants for the (001) state. The main results (in cm^?1) are

		35ClO2		37ClO2
$\text{ν}{}_0$		945.592 357(60)		939.602 909(66)		cm?1
μ′		1.788 39(13)		1.788 46(15)		D
μ″		1.791 95(10)		1.792 10(13)		D
δμ		?0.003 56(18)		?0.003 64(26)		D

     

10.

The microwave spectrum of the transient molecule chloro(sulphido)boron,ClBS: Substitution structure,dipole moment,quadrupole moment,and vibration-rotation analysis     

C. Kirby  H.W. Kroto 《Journal of Molecular Spectroscopy》1980,83(1):130-147

The rotational spectrum of the new reactive triatomic molecule chloro(sulphido)boron, ClBS, produced by the high-temperature reaction of gaseous dichloro disulphide, Cl₂S₂, and crystalline boron at ca. 1000°C was studied by microwave spectroscopy between 26.5 and 40 GHz. Ground state rotational constants have been obtained for 11 of the 12 isotopic variants involving ³⁵Cl, ³⁷Cl, ¹¹B, ¹⁰B, ³²S, ³³S, and ³⁴S; the isotopic shifts for the ground state lines of ³⁵Cl¹⁰B³⁴S from those of ³⁵Cl¹¹B³⁴S are too small and they are overlapped by the ¹¹B species. The abundance of rotational constant data has allowed a detailed comparison of various structure determination procedures to be made. The substitution method yields an extremely consistent ClS distance of 3.28715 ± 0.00005 Å. Application of the first moment condition allows the B atom, which lies close to the center of mass, to be quite accurately located. The resulting bond lengths are $\text{r(}\text{ClB}\text{) = 1.681 ± 0.001}\text{A}\text{?}$ and $\text{r(}\text{BS}\text{) = 1.606 ± 0.001}\text{A}\text{?}$. The more important derived spectroscopic parameters are:

	Ground state	$\text{ν}{}_2$	$\text{ν}{}_3$
A	3.1751882 (17)	3.1861249 (12)	3.1958722 (15)
B	0.39508266 (12)	0.39407878 (14)	0.39211484 (14)
C	0.35051504 (11)	0.34899779 (16)	0.34747411 (14)
$\text{ν}{}_0$	0	765.3551 (4)	519.5980 (4)

     

11.

High-resolution spectroscopy of 16 bands of OCS in the region 1975–2140 cm⁻¹ for diode laser calibration     

N. Hunt  S.C. Foster  J.W.C. Johns  A.R.W. McKellar 《Journal of Molecular Spectroscopy》1985,111(1):42-53

The spectrum of OCS with natural isotopic abundances has been measured in the 1975- to 2140-cm^?1 region with near-Doppler-limited resolution using a Fourier transform spectrometer. Sixteen bands have been analyzed, including the following five bands for the first time at high resolution:

	35Cl11B32S	35Cl10B32S	37Cl11B32S	35Cl10B32S
$\text{B}{}_0$	2796.7796(7)	2796.8613(14)	2722.9999(6)	2723.2127(17) MHz
$\text{D}{}_0$	344.0(8.0)	327.0(17.0)	321.0(7.0)	328.0(21.0) Hz
$\text{α}{}_2$	?7.4889(7)	?7.8745(15)	?7.2941(15)	?7.6742(17) MHz
$\text{α}{}_3$	3.4620(2)	3.7731(4)	3.4755(2)	3.6354(3) MHz
$\text{q}{}_2$	1.9942(9)	1.9160(7)	1.8954(7)	1.8190(7) MHz
$\text{eQq}\text{(Cl)}$	?42.54(1)	?42.56(2)	?33.53(1)	?33.58(3) MHz
μ	1.45(8)	—	—	— D

     

12.

Stark spectroscopy with the CO₂ laser: The ν₃ band of CD₃F     

G. Duxbury  S.M. Freund  J.W.C. Johns 《Journal of Molecular Spectroscopy》1976,62(1):99-108

The ν₃ band of CD₃F has been studied using coincidences with the 10.4 μm band of the CO₂ laser. The majority of the 150 resonances measured have been studied using the Lamb dip technique. These resonances have been analyzed, together with recent microwave results, to give the following vibration-rotation parameters and dipole moments in the ν₃ state.

16O13C32S	1000-0000	2009.228 cm?1
16O13C32S	1110-0110	2002.427 cm?1
18O12C32S	1000-0000	2026.147 cm?1
16O12C32S	0400-0000	2104.828 cm?1
16O12C32S	0510-0110	2115.169 cm?1

     

13.

Microwave spectrum,quadrupole hyperfine interaction,and electric dipole moment of the BrF molecule     

K.P.R Nair  J Hoeft  E Tiemann 《Journal of Molecular Spectroscopy》1979,78(3):506-513

The measurements of the microwave spectrum of BrF were carried out on the hyperfine components of J = 1 ← 0 and J = 2 ← 1 rotational transitions of ⁷⁹BrF and ⁸¹BrF. A direct diagonalization procedure of the energy matrix of the total Hamiltonian including Stark effect has been used. The following constants were derived:

	12CD3F
$\text{ν}{}_0$	992.29882 (19)	cm?1
$\text{B}$	20395.776 ± 0.08	MHz
$\text{A-A}{}_0$	?35.73 ± 0.61	MHz
$\text{D}{}_{\mathrm{J}}$	33.8 ± 0.5	kHz
$\text{D}{}_{\mathrm{JK}}$	203.9 ± 7	kHz
$\text{μ}{}_{\mathrm{\nu 3}}$	1.8964 ± 0.0015	D
$\text{μ}{}_{\mathrm{\nu 3}}\text{? μ}{}_0$	0.02617 ± 0.0005	D

     

14.

Laser Stark spectroscopy of formaldehyde-d2: The Coriolis coupled ν4 and ν6 fundamentals     

Dewitt Coffey  Chikashi Yamada  Eizi Hirota 《Journal of Molecular Spectroscopy》1977,64(1):98-108

Using CO₂ and N₂O lasers, we have measured and assigned nineteen ν₄ and nine ν₆ rotation-vibration resonances of the type ΔM = 0 and M = J. These transitions were combined with the zero-field pure rotational spectra in order to determine the two fundamental vibrational frequencies, the rotational constants of both excited states, the Coriolis coupling constant, and the dipole moments of each of the three states. The ground-state rotational constants and centrifugal distortion constants were taken from a microwave study and the centrifugal distortion constants of the excited states were assumed equal to those of the ground state. The following results were obtained (standard deviations in parentheses):

79BrF

81BrF

Be (MHz) 10 667.610 (60)

10 616.522 (70)

eq0Q (MHz) 1086.80 (30)

908.09 (20)

eq1Q (MHz) 1085.66 (60)

907.41

     

15.

CO₂ laser Stark spectroscopy of the Coriolis-coupled ν₂ and ν₅ bands of CD₃Br     

Kensuke Harada  Keiichi Tanaka  Takehiko Tanaka 《Journal of Molecular Spectroscopy》1983,98(2):349-374

The ν₂ (CD₃ symmetrical deformation) and ν₅ (CD₃ degenerate deformation) fundamental bands of CD₃Br were studied by 9.4- and 10.4-μm CO₂ laser Stark spectroscopy. Stark resonances originating from 28 and 53 rovibrational transitions of the ν₂ and ν₅ bands, respectively, were assigned for each of the isotopic species, CD₃⁷⁹Br and CD₃⁸¹Br. These two bands were simultaneously analyzed with explicit inclusion of the ν₂-ν₅ Coriolis interaction, yielding precise molecular constants in the ν₂ and ν₅ excited states as well as the Coriolis coupling constant. The molecular constants obtained are consistent between the two isotopic species and are in good agreement with the results of high-resolution infrared studies. The band origins and dipole moments are

		$\text{ν}{}_4$		$\text{ν}{}_6$
$\text{ν}{}_0$		938.0345 (6)		989.2519 (18)		(cm?1)
$\text{A}$		139 579 (150)		143 323 (150)		(MHz)
$\text{B}$		31 873.6 (5)		32 379.5 (7)		(MHz)
$\text{C}$		26 242.9 (6)		25 994.4 (8)		(MHz)
$\text{ξ}{}_{64}{}^{\mathrm{(a)}}$			136 178 (770)			(MHz)
μ		2.319 (10)		2.347 (4)		(D)
μ(ground state)			2.3464 (8)			(D)

     

16.

Collision-induced fundamental band of H2 in H2He and H2Ne mixtures at different temperatures     

S.Paddi Reddy  K.S. Chang 《Journal of Molecular Spectroscopy》1973,47(1):22-38

The collision-induced fundamental infrared absorption band of hydrogen in binary mixtures H₂He and H₂Ne at 77, 195, 273, and 298 K has been studied with absorption path lengths of 27 and 105 cm for gas densities up to 530 amagat for several base densities of hydrogen. In each of these mixtures the enhancement absorption profiles show, in addition to the usual splitting of the Q branch into the main Q_P and Q_R components, a splitting of the S(1) line into the S_P(1) and S_R(1) components at all the experimental temperatures and a secondary splitting of the main Q_P component into the Q_P(3) and Q_R(3) components at 273 and 298 K. The profiles of H₂He at 77 K also show a splitting of the S(0) line into S_P(0) and S_R(0). Integrated absorption coefficients were measured and binary and ternary absorption coefficients were derived. Van Kranendonk's theory of the ‘exponential-4’ model for the induced dipole moment was applied to the experimental binary absorption coefficients. The quadrupolar parts of these coefficients were calculated from the known molecular parameters and were then subtracted from the experimental values to obtain the overlap parts. The overlap parameters λ and ρ, giving respectively the magnitude and range of the overlap moment, were determined for each of the mixtures by obtaining the best fit of the calculated overlap part of the binary absorption coefficient as a function of temperature to the experimental values of the overlap parts. The values of λ, ρ, and μ(σ) (the overlap induced dipole moment at the Lennard-Jones intermolecular diameter σ) are as follows:

		CD379Br		CD381Br
$\text{ν}{}_2$		991.396 82 (18)		991.388 46 (17)		cm?1
$\text{ν}{}_5$		1055.469 00 (12)		1055.466 32 (12)		cm?1
$\text{μ}{}_0$		1.830 42 (52)		1.829 84 (47)		D
$\text{μ}{}_2$		1.829 93 (48)		1.829 57 (46)		D
$\text{μ}{}_5$		1.832 23 (60)		1.831 19 (56)		D

     

17.

CO laser-microwave double-resonance spectroscopy of H2CO with intense Stark field: Precise measurement of dipole moment in the ground and ν2 vibrational states     

Keiichi Tanaka  Akira Inayoshi  Kazuhiro Kijima  Takehiko Tanaka 《Journal of Molecular Spectroscopy》1982,95(1):182-193

Stark-shifted microwave transitions in the ground and ν₂ vibrational states of H₂CO were observed by means of CO laser-microwave double-resonance with intense electric field. High sensitivity and precision were attained by the use of multireflection absorption cell, optical-flat Stark plates, and microwave frequency stabilization. Dipole moments determined from some individual rotational transitions in the ground and ν₂ vibrational states are, in Debye, with uncertainties in parentheses,

Mixture	λ	ρ	μ(σ)
H2He	5.6 × 10?3	0.24 Å	2.92 × 10?2ea0
H2Ne	9.0 × 10?3	0.29 Å	4.85 × 10?2ea0

     

18.

The electronic spectrum of PrO. Energy linkages,rotational analysis,and hyperfine structure for systems XVII and XXI     

Michael Dulick  Robert W. Field  J.Cl. Beaufils  J. Schamps 《Journal of Molecular Spectroscopy》1981,87(1):278-288

Doppler-limited laser excitation spectra for four bands of PrO have been recorded: System XvII 0-0, System XXI 0-0 and 0–1, and the 0-0 intercombination between the upper and lower states, respectively, of Systems XVII and XXI. First lines in R and P branches prove that Systems XVII and XXI are, respectively, $\text{Ω}\text{′ = 4.5 ?}\text{Ω}\text{″ = 3.5}$ and $\text{Ω}\text{′ =}\text{Ω}\text{″ = 4.5}$. Hyperfine components are well resolved for all four excitation bands. Rotational and hyperfine constants are determined by least-squares fits of data from all four bands together. In addition, fluorescence spectra, recorded from various J′, v′ = 0 levels of the upper states of Systems XVII and XXI, reveal five new low-lying states. Principal constants (in cm^?1) for nine $\text{Ω-states}$ follow (1σ uncertainty in parentheses):

Transition		G.S.		$\text{ν}{}_2$		δμ
110 ← 111		2.3315 (1)		2.3472 (1)		0.0157 (1)
211 ← 212		2.3313 (1)		2.3471 (1)		0.0158 (1)
312 ← 313		2.3313 (1)		2.3470 (1)		0.0157 (1)
826 ← 827		2.3311 (1)		2.3466 (1)		0.0155 (1)
927 ← 928		—		2.3466 (1)		—

     

19.

Laser Stark spectroscopy in the 9.4-μm region: The ν2 and ν5 bands of methyl chloride-d3     

Chikashi Yamada  Eizi Hirota 《Journal of Molecular Spectroscopy》1977,64(1):31-46

About two hundred Stark resonances of the ν₂ and ν₅ vibration-rotation bands of CD₃³⁵Cl, using a 9.4 μm CO₂ laser as a source, have been measured. By combining these data with the zero-field microwave spectra the following molecular constants have been determined (with the standard deviations in parentheses):

State	$\text{T}{}_{\mathrm{v}}$	$\text{B}{}_{\mathrm{v}}$	$\text{d}\text{(hfs)}$
$\text{Ω′ = 4.5 (System XXI)}$	18 882.388 (2)	0.353001 (18)	0.12403 (71)
$\text{Ω′ = 4.5 (System XVII)}$	16 594.075 (1)	0.353736 (20)	0.12977 (67)
$\text{Ω}\text{″ = 3.5}$	3 887.15 (16)	0.35751 (28)	—
$\text{Ω}\text{″ = 3.5}$	2 931.66 (15)	0.35712 (21)	—
$\text{Ω}\text{″ = 4.5}$	2 155.16 (30)	0.36264 (67)	—
$\text{Ω}\text{″ = 5.5}$	2 099.16 (31)	0.35079 (71)	—
$\text{Ω}\text{″ = 3.5}$	2 064.34 (13)	0.35654 (20)	—
$\text{Ω″ = 4.5 (System XXI)}$	217.383 (1)	0.362134 (20)	0.27744 (66)
$\text{Ω″ = 3.5 (System XVII)}$	0.0	0.360948 (16)	?0.00809 (85)

     

20.

Absorption spectrum of BS₂ at 4°K     

J.M. Brom  W. Weltner 《Journal of Molecular Spectroscopy》1973,45(1):82-98

BS₂, trapped in neon matrices at 4°K, exhibits extensive progressions in the A²Π_u ← X²Π_g and $\text{B}{}^2\text{Σ}{}_{\mathrm{u}}{}^{\mathrm{+}}\text{← X}{}^2\text{Π}{}_{\mathrm{g}}$ systems. From these transitions, those observed in the infrared, and a reinterpretation of gas-phase data, the following molecular constants (in solid neon) are obtained for linear symmetric ¹¹BS₂ (in cm^?1):

		$\text{ν}{}_2$		$\text{ν}{}_5$
$\text{ν}{}_0$		1 028.67275 (15)		1 059.96970 (11)		(cm?1)
$\text{A}$		78 765.20 (89)		78 030.21 (109)		(MHz)
$\text{B}{}^1$		10 805.29 (26)		10 860.10 (13)		(MHz)
$\text{Aζ}{}_5$				?25 080.77 (99)		(MHz)
$\text{D}$			8 756.0 (43)			(MHz)
μ		1.90741 (33)		1.90607 (36)		(D)
μ(ground state)			1.90597 (33)			(D)

     

$\text{B}{}^2\text{Σ}{}_{\mathrm{u}}{}^{\mathrm{+}}$	T0 = 24,072	$\text{ν}{}_1\text{= 516}$
$\text{A}{}^2\text{Π}{}_{\mathrm{u}}$	T0 = 13.766	$\text{ν}{}_1\text{= 506}$
	A0 = ?263	$\text{ν}{}_2\text{= 311}$
		$\text{ν}{}_3\text{= 1535}$
$\text{X}{}^2\text{Π}{}_{\mathrm{g}}$	A0 = ?440	$\text{ν}{}_1\text{= 510}$
		$\text{ν}{}_2\text{= ～120}$
		$\text{ν}{}_3\text{= 1015}$

Stark spectroscopy with the CO laser: The ν2 fundamentals of H2CO and D2CO

The ν₂ (CO stretching) vibration-rotation bands of H₂CO and D₂CO near 5.8 μm have been studied using the technique of laser Stark spectroscopy. The following vibrational and rotational constants have been determined:

The absorption spectrum of the Ag2 molecule

The high dispersion absorption spectrum of the Ag₂ molecule has been photographed in the ～5300–1500-Å region. Observations include the previously reported A ← X, B ← X, C ← X, D ← X, and E ← X transitions and a new H ← X transition which occurs in the vacuum ultraviolet. Extensive spectral blending precluded detailed rotational analyses, but the band structures are consistent with $\text{ΔΩ}\text{= 0}$ and $\text{ΔΩ}\text{≥1}$ for D-X and C-X, respectively. The H state is perturbed and probably predissociated. The following molecular constants (in cm^?1) were obtained from fitting bandhead data to the usual expressions:

Laser Stark spectroscopy in the 10 μm region: The ν3 bands of CH3F

Laser Stark spectroscopy of the ν₃ band of CH₃F has been carried out using coincidences with the 9.4 μm band CO₂ laser lines. About 350 Stark resonances were measured for the ν₃ fundamental bands of ¹²CH₃F and ¹³CH₃F. About 30 of them were measured by using a Stark-Lamb dip technique to increase the resolution and the accuracy of the data. These Stark resonances, together with the recent results of infrared-microwave two-photon Lamb dip measurements, were analyzed to give the following vibration-rotation parameters and the dipole moments in the ν₃ state,

Acoustical measurement of solid state non-linearity: Application to CsCdF3 and KZnF3

Combination of the results of two sets of measurements on the same crystalline samples of CsCdF₃ and KZnF₃ has made possible the evaluation of the third-order elastic (TOE) constants of these two fluoroperovskites. In the first technique the hydrostatic pressure dependence of the velocity of ultrasonic waves of different propagation and polarization directions has been measured to determine three linear combinations of TOE constants. In the second technique the fundamental and the second harmonic amplitudes of an initially sinusoidal longitudinal ultrasonic wave of finite amplitude propagating along the principal directions have been measured to determine three other linear combinations. Combination of the two sets of data leads to the following room temperature values of the TOE constants (in units of 10¹² dynes/cm²):

The 10.4 μm CO2 laser Stark spectra of the ν4 and the ν9 bands of 1,1 difluoroethylene

The ν₄ and the ν₉ bands of CF₂CH₂ have been studied using coincidences with the 10.4 μm band of the CO₂ laser and the 10.9 μm band of the N₂O laser. These resonances have been analyzed, together with recent microwave results, to give the following vibration-rotation parameters and dipole moments in the ν₄ and ν₉ states

The ν3 fundamental band of HDCO

The ν₃ fundamental band (CO stretch) of HDCO at 1724 cm^?1 has been studied using both conventional infrared absorption and CO laser Stark spectroscopy. In addition to the excited-state (v₃ = 1) rotational constants, improved constants for the ground state of HDCO have been obtained by combining previous microwave data with some infrared combination differences. The following constants were determined:

CO2 and N2O laser Stark spectroscopy of the ν1 band of the ClO2 radical

The ν₁ fundamental band of the ClO₂ radical has been studied by means of the 10.6-μm CO₂ and N₂O laser Stark spectroscopy. More than 250 and 150 Stark resonances were assigned for the ³⁵ClO₂ and ³⁷ClO₂ species, respectively, and were analyzed together with the recent microwave and laser-microwave double resonance results to give molecular constants including spin-rotation interaction constants. The ν₁ band origins and electric dipole moments both in the ground and ν₁ states were determined accurately

High-resolution Fourier transform spectroscopy of the ν2 and ν3 fundamentals of nitrosyl fluoride,FNO

The ν₂ and ν₃ fundamentals of FNO have been recorded with a Fourier transform spectrophotometer at an apodized resolution of approximately 0.004 cm^?1. The Fourier infrared data have been analyzed together with previous microwave data to yield improved molecular parameters for the (000) and (010) vibrational states and the first set of constants for the (001) state. The main results (in cm^?1) are

The microwave spectrum of the transient molecule chloro(sulphido)boron,ClBS: Substitution structure,dipole moment,quadrupole moment,and vibration-rotation analysis

The rotational spectrum of the new reactive triatomic molecule chloro(sulphido)boron, ClBS, produced by the high-temperature reaction of gaseous dichloro disulphide, Cl₂S₂, and crystalline boron at ca. 1000°C was studied by microwave spectroscopy between 26.5 and 40 GHz. Ground state rotational constants have been obtained for 11 of the 12 isotopic variants involving ³⁵Cl, ³⁷Cl, ¹¹B, ¹⁰B, ³²S, ³³S, and ³⁴S; the isotopic shifts for the ground state lines of ³⁵Cl¹⁰B³⁴S from those of ³⁵Cl¹¹B³⁴S are too small and they are overlapped by the ¹¹B species. The abundance of rotational constant data has allowed a detailed comparison of various structure determination procedures to be made. The substitution method yields an extremely consistent ClS distance of 3.28715 ± 0.00005 Å. Application of the first moment condition allows the B atom, which lies close to the center of mass, to be quite accurately located. The resulting bond lengths are $\text{r(}\text{ClB}\text{) = 1.681 ± 0.001}\text{A}\text{?}$ and $\text{r(}\text{BS}\text{) = 1.606 ± 0.001}\text{A}\text{?}$. The more important derived spectroscopic parameters are:

High-resolution spectroscopy of 16 bands of OCS in the region 1975–2140 cm−1 for diode laser calibration

The spectrum of OCS with natural isotopic abundances has been measured in the 1975- to 2140-cm^?1 region with near-Doppler-limited resolution using a Fourier transform spectrometer. Sixteen bands have been analyzed, including the following five bands for the first time at high resolution:

Stark spectroscopy with the CO2 laser: The ν3 band of CD3F

The ν₃ band of CD₃F has been studied using coincidences with the 10.4 μm band of the CO₂ laser. The majority of the 150 resonances measured have been studied using the Lamb dip technique. These resonances have been analyzed, together with recent microwave results, to give the following vibration-rotation parameters and dipole moments in the ν₃ state.

Microwave spectrum,quadrupole hyperfine interaction,and electric dipole moment of the BrF molecule

The measurements of the microwave spectrum of BrF were carried out on the hyperfine components of J = 1 ← 0 and J = 2 ← 1 rotational transitions of ⁷⁹BrF and ⁸¹BrF. A direct diagonalization procedure of the energy matrix of the total Hamiltonian including Stark effect has been used. The following constants were derived:

Laser Stark spectroscopy of formaldehyde-d2: The Coriolis coupled ν4 and ν6 fundamentals

Using CO₂ and N₂O lasers, we have measured and assigned nineteen ν₄ and nine ν₆ rotation-vibration resonances of the type ΔM = 0 and M = J. These transitions were combined with the zero-field pure rotational spectra in order to determine the two fundamental vibrational frequencies, the rotational constants of both excited states, the Coriolis coupling constant, and the dipole moments of each of the three states. The ground-state rotational constants and centrifugal distortion constants were taken from a microwave study and the centrifugal distortion constants of the excited states were assumed equal to those of the ground state. The following results were obtained (standard deviations in parentheses):

CO2 laser Stark spectroscopy of the Coriolis-coupled ν2 and ν5 bands of CD3Br

The ν₂ (CD₃ symmetrical deformation) and ν₅ (CD₃ degenerate deformation) fundamental bands of CD₃Br were studied by 9.4- and 10.4-μm CO₂ laser Stark spectroscopy. Stark resonances originating from 28 and 53 rovibrational transitions of the ν₂ and ν₅ bands, respectively, were assigned for each of the isotopic species, CD₃⁷⁹Br and CD₃⁸¹Br. These two bands were simultaneously analyzed with explicit inclusion of the ν₂-ν₅ Coriolis interaction, yielding precise molecular constants in the ν₂ and ν₅ excited states as well as the Coriolis coupling constant. The molecular constants obtained are consistent between the two isotopic species and are in good agreement with the results of high-resolution infrared studies. The band origins and dipole moments are

Collision-induced fundamental band of H2 in H2He and H2Ne mixtures at different temperatures

The collision-induced fundamental infrared absorption band of hydrogen in binary mixtures H₂He and H₂Ne at 77, 195, 273, and 298 K has been studied with absorption path lengths of 27 and 105 cm for gas densities up to 530 amagat for several base densities of hydrogen. In each of these mixtures the enhancement absorption profiles show, in addition to the usual splitting of the Q branch into the main Q_P and Q_R components, a splitting of the S(1) line into the S_P(1) and S_R(1) components at all the experimental temperatures and a secondary splitting of the main Q_P component into the Q_P(3) and Q_R(3) components at 273 and 298 K. The profiles of H₂He at 77 K also show a splitting of the S(0) line into S_P(0) and S_R(0). Integrated absorption coefficients were measured and binary and ternary absorption coefficients were derived. Van Kranendonk's theory of the ‘exponential-4’ model for the induced dipole moment was applied to the experimental binary absorption coefficients. The quadrupolar parts of these coefficients were calculated from the known molecular parameters and were then subtracted from the experimental values to obtain the overlap parts. The overlap parameters λ and ρ, giving respectively the magnitude and range of the overlap moment, were determined for each of the mixtures by obtaining the best fit of the calculated overlap part of the binary absorption coefficient as a function of temperature to the experimental values of the overlap parts. The values of λ, ρ, and μ(σ) (the overlap induced dipole moment at the Lennard-Jones intermolecular diameter σ) are as follows:

CO laser-microwave double-resonance spectroscopy of H2CO with intense Stark field: Precise measurement of dipole moment in the ground and ν2 vibrational states

Stark-shifted microwave transitions in the ground and ν₂ vibrational states of H₂CO were observed by means of CO laser-microwave double-resonance with intense electric field. High sensitivity and precision were attained by the use of multireflection absorption cell, optical-flat Stark plates, and microwave frequency stabilization. Dipole moments determined from some individual rotational transitions in the ground and ν₂ vibrational states are, in Debye, with uncertainties in parentheses,

The electronic spectrum of PrO. Energy linkages,rotational analysis,and hyperfine structure for systems XVII and XXI

Doppler-limited laser excitation spectra for four bands of PrO have been recorded: System XvII 0-0, System XXI 0-0 and 0–1, and the 0-0 intercombination between the upper and lower states, respectively, of Systems XVII and XXI. First lines in R and P branches prove that Systems XVII and XXI are, respectively, $\text{Ω}\text{′ = 4.5 ?}\text{Ω}\text{″ = 3.5}$ and $\text{Ω}\text{′ =}\text{Ω}\text{″ = 4.5}$. Hyperfine components are well resolved for all four excitation bands. Rotational and hyperfine constants are determined by least-squares fits of data from all four bands together. In addition, fluorescence spectra, recorded from various J′, v′ = 0 levels of the upper states of Systems XVII and XXI, reveal five new low-lying states. Principal constants (in cm^?1) for nine $\text{Ω-states}$ follow (1σ uncertainty in parentheses):

Laser Stark spectroscopy in the 9.4-μm region: The ν2 and ν5 bands of methyl chloride-d3

About two hundred Stark resonances of the ν₂ and ν₅ vibration-rotation bands of CD₃³⁵Cl, using a 9.4 μm CO₂ laser as a source, have been measured. By combining these data with the zero-field microwave spectra the following molecular constants have been determined (with the standard deviations in parentheses):

Absorption spectrum of BS2 at 4°K

BS₂, trapped in neon matrices at 4°K, exhibits extensive progressions in the A²Π_u ← X²Π_g and $\text{B}{}^2\text{Σ}{}_{\mathrm{u}}{}^{\mathrm{+}}\text{← X}{}^2\text{Π}{}_{\mathrm{g}}$ systems. From these transitions, those observed in the infrared, and a reinterpretation of gas-phase data, the following molecular constants (in solid neon) are obtained for linear symmetric ¹¹BS₂ (in cm^?1):