Rotational analysis of some electronic transitions in the spectrum of PrO

Rotational analysis of 13 emission bands of PrO belonging to 10 different systems was carried out. The derived constants are as follows:

     

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:

$\text{ν}{}_0$	$\text{B′}$	$\text{D′ × 10}{}^7$	$\text{B″}$	$\text{D″ × 10}{}^7$
18 665.19(1)	0.3530(1)	1.80(5)	0.3622(1)	2.85(1)
18 613.22(1)	0.3517(1)	0.4(3)	0.3606(1)	2.4(2)
17 842.32(1)	0.3560(1)	3.0(1)	0.3621(1)	2.7(1)
17 796.09(4)	0.3532(3)	2.4(8)	0.3604(2)	2.7(6)
18 628.22(3)	0.3530(6)	1.8(8)	0.3620(5)	2.7(7)
14 426.12(2)	0.3519(1)	5.5(6)	0.3620(1)	1.9(6)
13 541.44(2)	0.3500(2)	3.7(5)	0.3605(2)	2.3(5)
13 645.78(8)	0.3511(3)	3.1(5)	0.3620(2)	2.8(5)
12 961.98(4)	0.3445(4)	4.5(4)	0.3603(3)	2.3(7)
9 600.47(1)	0.3454(1)	2.8(2)	0.3620(1)	3.0(3)
16 591.29(1)	0.3536(1)	0.5(2)	0.3610(1)	2.6(1)
11 912.89(1)	0.3480(2)	8.5(8)	0.3610(1)	2.2(6)
10 429.62(2)	0.3450(1)	3.1(1)	0.3610(1)	3.0(3)

     

3.

Electronic structure of PrO: An analysis summary     

M. Dulick  R.W. Field 《Journal of Molecular Spectroscopy》1985,113(1):105-141

The (0,0) bands of nine prominent electronic transitions, Systems X, XI, and XVI through XXII, in the wavelength region 500–800 nm were studied. High-precision (±0.005 cm^?1), Doppler-limited, selectively detected cw-dye laser fluorescence excitation spectra for Systems XVI through XXII were recorded and analyzed. Definitive Ω assignments for the upper and lower states of these transitions were established from identified first lines in the P and R branches. Resolved fluorescence studies revealed 22 additional electronic transitions in the same wavelength region, many of which provide energy linkages between the upper or lower states of previously observed transitions. The comprehensive energy level diagram assembled from 31 electronic transition linkages comprises a total of 22 upper and lower electronic levels. Ω assignments and relative energies for the electronic states of the transitions studied (including Systems XIV and IX identified in fluorescence and the proposed assignment for System VI) are

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 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):

System	Ω′	$\text{T′}{}_0\text{(}\text{cm}{}^{\mathrm{?1}}\text{)}$	$\text{Ω″}$	$\text{T″}{}_0\text{(}\text{cm}{}^{\mathrm{?1}}\text{)}$
VI	5.5	11102	4.5	2157
IX	4.5	16597	3.5	3887
X	5.5	13259	4.5	220
XI	5.5	13865	4.5	220
XIV	5.5	16595	4.5	2157
XVI	5.5	19169	4.5	3720
XVII	4.5	16597	3.5	0
XVIII	7.5	21321	6.5	3965
XIX	6.5	19687	5.5	2111
XX	5.5	18069	4.5	220
XXI	4.5	18885	4.5	220
XXII	5.5	19169	4.5	220

     

5.

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):

		$\text{ν}{}_2$		$\text{ν}{}_5$
$\text{ν}{}_0$		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)

     

6.

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

		$\text{ν}{}_4$		$\text{ν}{}_6$
$\text{ν}{}_0$		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)

     

7.

Fluorescence of the bromine molecules affer selective excitation by a single-mode krypton-lon laser     

G. De Vlieger  F. Claesens  H. Eisendrath 《Journal of Molecular Spectroscopy》1980,83(2):339-342

Optical-optical double-resonance (OODR) spectra of CaF are recorded, with reduced Doppler broadening, using two cw, single-mode dye lasers. Molecular constants for E²Σ⁺ and $\text{E′}{}^2\text{Π}$ are obtained from rotational analysis of the 0-0 and 1-0 E²Σ⁺-A²Π bands and the 0-0 $\text{E′}{}^2\text{Π}\text{-A}{}^2\text{Π}$ band, supplemented by fragmentary observations on the E′-A 0-1 and 1-1 bands:

		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

     

8.

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,

				Main parameters
			$\text{E}{}^2\text{Σ}{}^{\mathrm{+}}$		$\text{E′}{}^2\text{Π}$
	$\text{T}{}_0$				34 171.218(2)	34 477.413(3)
	$\text{Δ}\text{G}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$				640.912(3)	668.991(24)
	$\text{B}{}_{\mathrm{<mtext>e</mtext>}}$		0.364393(18)		0.368423(50)
	$\text{α}{}_{\mathrm{<mtext>e</mtext>}}$		0.002266(18)		0.002375(50)
	$\text{A(0)}$			16.483(4)

     

9.

The electric dipole moment of the hydrogen-bonded heterodimer HCN⋯HF. An investigation of the conditions leading to inadequacy of the second- and fourth-order perturbation theories of the Stark effect for linear molecules     

A.C Legon  D.J Millen  S.C Rogers 《Journal of Molecular Spectroscopy》1978,70(2):209-215

We have detected large deviations of the M_J = 0, J = 2 ← 1 Stark effect transition in the linear molecule HCN?HF from predictions of second-, and even fourth-, order perturbation theory. In order to account satisfactorily for the observed effect it has been necessary to set up and diagonalize the appropriate energy matrix. Smaller deviations in the case of M_J = 1, J = 2 ← 1 have likewise been treated. The values of the electric dipole moment for HCN?HF calculated from these transitions, which show large and small deviations from second-order theory, and from one (M_J = 3, J = 4 ← 3) which shows effectively zero deviation, are now consistent and are as follows:

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)		—

     

10.

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

$\text{J + 1 ← J}$	$\text{M}{}_{\mathrm{J}}$		μ/D
2 ← 1	0		5.627
	1		5.601
4 ← 3	3		5.608
		Mean	5.612

     

11.

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

	$\text{ν}{}_4$ 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

     

12.

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:

	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)

     

13.

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):

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

     

14.

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:

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

     

15.

The vibration-rotation fundamental of NO     

J.W.C. Johns  J. Reid  D.W. Lepard 《Journal of Molecular Spectroscopy》1977,65(1):155-162

The vibration-rotation fundamental of nitric oxide has been reexamined under conditions of moderately high resolution. The new measurements have been combined with earlier measurements on the pure rotation spectrum to give improved vibration-rotation constants. The main results are (in cm^?1)

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

     

16.

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):

Constant		$\text{v = 0}$		$\text{v = 1}$
ν		0		1875.972 ± 0.001
$\text{A}{}_{\mathrm{<mtext>eff</mtext>}}\text{= A + (0 +}\text{1}\text{2}\text{p)}$		123.1393 ± 0.0030		122.8935 ± 0.0042
$\text{B}{}_{\mathrm{<mtext>eff</mtext>}}\text{= B ?}\text{1}\text{2}\text{q}$		1.696115 ± 0.000011		1.678544 ± 0.000032

     

17.

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

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)

     

18.

The A1Π-X1Σ band system of CD+: Spectroscopic constants and isotope shifts     

A. Antić-Jovanović  V. Bojović  D.S. Pešić  S. Weniger 《Journal of Molecular Spectroscopy》1979,75(2):197-204

Six bands of the A¹Π-X¹Σ system of CD⁺ in the region 3800–4800 Å have been recorded in emission using an aluminum hollow-cathode discharge in the HeC₂H₂ mixture. From the vibrational and rotational analysis of the observed bands, the following constants (cm^?1) are obtained:

		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

     

19.

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,

		$\text{T}{}_{00}$		$\text{ω}{}_{\mathrm{e}}$		$\text{ω}{}_{\mathrm{e}}\text{x}{}_{\mathrm{e}}$		$\text{ω}{}_{\mathrm{e}}\text{y}{}_{\mathrm{e}}$		$\text{B}{}_{\mathrm{e}}$		$\text{D}{}_{\mathrm{e}}\text{·10}{}^4$		$\text{α}{}_{\mathrm{e}}$
$\text{A}{}^1\text{Π}$		23 747.5		1367.3		60.6		0.75		6.428		5.7		0.388
$\text{X}{}^1\text{Σ}$		0		2035						7.650		4.1		0.190
				(2101.6)		(33.3)

     

20.

Continuous wave dye laser excitation spectroscopy CaF A2Πr-X2Σ+     

Robert W. Field  David O. Harris  Takehiko Tanaka 《Journal of Molecular Spectroscopy》1975,57(1):107-117

Excitation spectra for the CaF A²Π-X²Σ(0, 0), (1, 1), and (1, 0) bands have been observed and assigned. The rotational analysis of the CaF A-X and B-X bands by B. S. Mohanty and K. N. Upadhya [Ind. J. Pure Appl. Phys.5, 523 (1967)] is shown to be incorrect. Because it is possible to make independent rotational assignments of each line in an excitation spectrum by observing frequency differences and relative intensities in photoluminescence spectra, tunable laser excitation spectroscopy promises less ambiguity than traditional techniques for assignment of dense, badly overlapped spectra.The following spectroscopic constants (in cm^?1) are obtained for the CaF A²Π and X²Σ states. Numbers in parentheses correspond to three standard deviations uncertainty in the last digit.

	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	$\text{D}$

     

	$\text{X}{}^2\text{Σ}$		$\text{A}{}^2\text{Π}$
$\text{ν}{}_{00}$	0	${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$	16493.1(6)
		${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$	16565.6(6)
$\text{Δ}\text{G(}\text{1}\text{2}\text{)}$	581.1(9)	${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$	586.8(9)
$\text{B}{}_{\mathrm{e}}$	0.3385(11)		0.3436(12)
$\text{B}{}_{\mathrm{e}}\text{(}\text{Ω}\text{=}\text{3}\text{2}\text{) ? B}{}_3\text{(}\text{Ω}\text{=}\text{1}\text{2}\text{)}$	—		0.00312(21)
α	0.00255(48)		0.00283(45)
$\text{D(}\text{estimated}\text{)}$	4.44 × 10?7		4.55 × 10?7
γ(spin-spin)	|γ| < 3 × 10?3		—
$\text{A}{}_0\text{(}\text{spin-orbit}\text{)}$	—		73.4(9)
$\text{p(}\text{lambda doubling}\text{)}$	—		?0.045(4)

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:

Electronic structure of PrO: An analysis summary

The (0,0) bands of nine prominent electronic transitions, Systems X, XI, and XVI through XXII, in the wavelength region 500–800 nm were studied. High-precision (±0.005 cm^?1), Doppler-limited, selectively detected cw-dye laser fluorescence excitation spectra for Systems XVI through XXII were recorded and analyzed. Definitive Ω assignments for the upper and lower states of these transitions were established from identified first lines in the P and R branches. Resolved fluorescence studies revealed 22 additional electronic transitions in the same wavelength region, many of which provide energy linkages between the upper or lower states of previously observed transitions. The comprehensive energy level diagram assembled from 31 electronic transition linkages comprises a total of 22 upper and lower electronic levels. Ω assignments and relative energies for the electronic states of the transitions studied (including Systems XIV and IX identified in fluorescence and the proposed assignment for System VI) are

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):

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 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

Fluorescence of the bromine molecules affer selective excitation by a single-mode krypton-lon laser

Optical-optical double-resonance (OODR) spectra of CaF are recorded, with reduced Doppler broadening, using two cw, single-mode dye lasers. Molecular constants for E²Σ⁺ and $\text{E′}{}^2\text{Π}$ are obtained from rotational analysis of the 0-0 and 1-0 E²Σ⁺-A²Π bands and the 0-0 $\text{E′}{}^2\text{Π}\text{-A}{}^2\text{Π}$ band, supplemented by fragmentary observations on the E′-A 0-1 and 1-1 bands:

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 electric dipole moment of the hydrogen-bonded heterodimer HCN⋯HF. An investigation of the conditions leading to inadequacy of the second- and fourth-order perturbation theories of the Stark effect for linear molecules

We have detected large deviations of the M_J = 0, J = 2 ← 1 Stark effect transition in the linear molecule HCN?HF from predictions of second-, and even fourth-, order perturbation theory. In order to account satisfactorily for the observed effect it has been necessary to set up and diagonalize the appropriate energy matrix. Smaller deviations in the case of M_J = 1, J = 2 ← 1 have likewise been treated. The values of the electric dipole moment for HCN?HF calculated from these transitions, which show large and small deviations from second-order theory, and from one (M_J = 3, J = 4 ← 3) which shows effectively zero deviation, are now consistent and are as follows:

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

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 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:

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 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:

The vibration-rotation fundamental of NO

The vibration-rotation fundamental of nitric oxide has been reexamined under conditions of moderately high resolution. The new measurements have been combined with earlier measurements on the pure rotation spectrum to give improved vibration-rotation constants. The main results are (in cm^?1)

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):

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

The A1Π-X1Σ band system of CD+: Spectroscopic constants and isotope shifts

Six bands of the A¹Π-X¹Σ system of CD⁺ in the region 3800–4800 Å have been recorded in emission using an aluminum hollow-cathode discharge in the HeC₂H₂ mixture. From the vibrational and rotational analysis of the observed bands, the following constants (cm^?1) are obtained:

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,

Continuous wave dye laser excitation spectroscopy CaF A2Πr-X2Σ+

Excitation spectra for the CaF A²Π-X²Σ(0, 0), (1, 1), and (1, 0) bands have been observed and assigned. The rotational analysis of the CaF A-X and B-X bands by B. S. Mohanty and K. N. Upadhya [Ind. J. Pure Appl. Phys.5, 523 (1967)] is shown to be incorrect. Because it is possible to make independent rotational assignments of each line in an excitation spectrum by observing frequency differences and relative intensities in photoluminescence spectra, tunable laser excitation spectroscopy promises less ambiguity than traditional techniques for assignment of dense, badly overlapped spectra.The following spectroscopic constants (in cm^?1) are obtained for the CaF A²Π and X²Σ states. Numbers in parentheses correspond to three standard deviations uncertainty in the last digit.