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Constants of diatomic molecules

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Klaus P. Huber and Gerhard H. Herzberg

Data collected through August, 1977

Symbols used in the table of constants
State electronic state and / or symmetry symbol
Te minimum electronic energy (cm-1)
ωe vibrational constant – first term (cm-1)
ωexe vibrational constant – second term (cm-1)
ωeye vibrational constant – third term (cm-1)
Be rotational constant in equilibrium position (cm-1)
αe rotational constant – first term (cm-1)
γe rotation-vibration interaction constant (cm-1)
De centrifugal distortion constant (cm-1)
βe rotational constant – first term, centrifugal force (cm-1)
re internuclear distance (Å)
Trans. observed transition(s) corresponding to electronic state
ν00 position of 0-0 band (units noted in table)
Diatomic constants for 28SiH
E 2Sigma+ [53411.2] 1    [7.528]   [3.92E-4]  [1.5172] E larrow X V 52399.19 Z
missing citation
D 2Delta [49522.1] 1    [7.90] 2     [1.481] D larrow X V 48510.1 Z
Verma, 1965; missing citation
B 2Sigma+ [31842.2] 1    [6.62] 3 4     [1.618] B larrow X R 30830.2 3 Z
missing citation; Bollmark, Klynning, et al., 1971
C 2Sigma+ [31832.4] 5    [1.17] 3     [3.85] C larrow X R 30820.4 3 Z
Verma, 1965; Bollmark, Klynning, et al., 1971
"Slightly diffuse" weak absorption bands in the region 25600 - 26700 cm-1.
Thrush, 1960
A 2Delta 24300.4 6 1858.90 7 Z 99.175  7.4664 7 0.3445 -0.04185 [5.24E-4] 8  1.52347 A lrarrow X 9 10 R 24193.04 Z
missing citation; Douglas, 1957; missing citation; Klynning and Lindgren, 1967; Herzberg, Lagerqvist, et al., 1969
X 2Pir 0 11 2041.80 7 Z 35.51  7.4996 7 12 0.2190 0.0017 [3.97E-4]  1.52010 13  


1Only v=0 observed
2Increasing diffuseness with increasing N on account of predissociation.
3Deperturbed constants of Bollmark, Klynning, et al., 1971 whose T0 values correspond to nu00 + 1079.5 [see Klynning and Lindgren, 1967]. As in similar cases, nu00 refers to the zero-point of the Hill-VanVleck expression for the ground state. Interaction parameter HB,C = 16.1 cm-1. The v numbering of the C level is uncertain.
4Strongly predissociated above N=2.
5Only one level observed
6A0 = 3.58 Klynning and Lindgren, 1967, A1 = 3.11 Klynning and Lindgren, 1967, A2 = 2.59 Klynning and Lindgren, 1967. Discussion of second order spin-orbit splittings Veseth, 1971.
7Recalculated Herzberg, Lagerqvist, et al., 1969 from data for v=0, 1, 2 Klynning and Lindgren, 1967.
8missing note
9 Smith, 1969 gives a radiative lifetime of 0.7 mus for both SiH and SiD corresponding to f00 = 0.0037 Smith and Liszt, 1971; see also Grevesse and Sauval, 1971.
10Potential functions, Franck-Condon factors Rao and Lakshman, 1971, Smith and Liszt, 1971
11A0 = +142.83. A1 = +143.43. A2 = +144.04. Slight J dependence Klynning and Lindgren, 1967.
12For Lambda-doubling constants (p0 = 0.0819, q0 = 0.00831) see Klynning and Lindgren, 1967, missing citation; the extrapolated splitting of the v=0, J=1/2 level is Delta vfe = +0.0978 cm-1 (2932 ± 20 MHz) missing citation; ab initio calculations Wilson and Richards, 1975 predict Delta vfe= 0.1057 cm-1 (3168 MHz).
13Extensive theoretical calculations 17
14From the predissociation in B 2Sigma+ assuming dissociation into 1D + 2S at the predissociation limit Verma, 1965. According to Douglas, 1957 extrapolation of the vibrational levels in A 2Delta gives very nearly the same limit.
15From D00(SiH), I.P.(Si), and D00(SiH+) Douglas and Lutz, 1970.
16D1 = 6.08E-4, D2 = 7.36E-4.
17Hartree-Fock wavefunctions and energies Cade and Huo, 1967, charge distributions Cade, Bader, et al., 1969, spectroscopic constants Meyer and Rosmus, 1975.
18From the value for SiH, confirmed by the observed predissociation in B 2Sigma+.
19Recalculated from the data of Verma, 1965.
20Deperturbed constants of Bollmark, Klynning, et al., 1971 whose T0 values correspond to nu00 + 797.50 [see Klynning and Lindgren, 1967]. Interaction parameter HB,C = 5.87 cm-1. See 3.
21Increasing linewidth above N=8 indicating predissociation.
22A0 = 3.45, A1 = 3.42, A2 = 2.14 Klynning and Lindgren, 1967; see also Veseth, 1971.
23D1 = 1.524E-4, D2 = 1.708E-4.
24A0 = +142.73, A1 = +143.10; A2= +143.76; slight J dependence Klynning and Lindgren, 1967.
25 Klynning and Lindgren, 1967 give Lambda-doubling constants (p= 0.039, q= 0.0024).


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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Verma, 1965
Verma, R.D., The spectrum of SiH and SiD, Can. J. Phys., 1965, 43, 2136. [all data]

Bollmark, Klynning, et al., 1971
Bollmark, P.; Klynning, L.; Pages, P., Rotational analysis of the 3250 Å bands of SiH and SiD, Phys. Scr., 1971, 3, 219-222. [all data]

Thrush, 1960
Thrush, B.A., Absorption spectra of diatomic radicals containing boron or silicon, Nature (London), 1960, 186, 1044. [all data]

Douglas, 1957
Douglas, A.E., The spectrum of silicon hydride, Can. J. Phys., 1957, 35, 71. [all data]

Klynning and Lindgren, 1967
Klynning, L.; Lindgren, B., The spectra of silicon hydride and silicon deuteride, Ark. Fys., 1967, 33, 73. [all data]

Herzberg, Lagerqvist, et al., 1969
Herzberg, G.; Lagerqvist, A.; McKenzie, B.J., Absorption spectrum of SiH in the vacuum ultraviolet, Can. J. Phys., 1969, 47, 1889. [all data]

Veseth, 1971
Veseth, L., Second-order spin-orbit splitting in 2«DELTA» states of diatomic molecules, Physica (Amsterdam), 1971, 56, 286. [all data]

Smith, 1969
Smith, W.H., Lifetimes and total transition probabilities for NH, SiH, and SiD, J. Chem. Phys., 1969, 51, 520. [all data]

Smith and Liszt, 1971
Smith, W.H.; Liszt, H.S., Franck-Condon factors and absolute oscillator strengths for NH, SiH, S2 and SO, J. Quant. Spectrosc. Radiat. Transfer, 1971, 11, 45. [all data]

Grevesse and Sauval, 1971
Grevesse, N.; Sauval, A.J., Oscillator strengths for SiH and SiH+ deduced from the solar spectrum, J. Quant. Spectrosc. Radiat. Transfer, 1971, 11, 65. [all data]

Rao and Lakshman, 1971
Rao, T.V.R.; Lakshman, S.V.J., The true potential energy curves and Franck-Condon factors of SiH and SiH+ molecules, Physica, 1971, 56, 322. [all data]

Wilson and Richards, 1975
Wilson, I.D.L.; Richards, W.G., «LAMBDA»-type doubling in SiH molecule, Nature (London), 1975, 258, 133. [all data]

Douglas and Lutz, 1970
Douglas, A.E.; Lutz, B.L., Spectroscopic identification of the SiH+ molecule: the A 1«pi»-X1+ system, Can. J. Phys., 1970, 48, 247. [all data]

Cade and Huo, 1967
Cade, P.E.; Huo, W.M., Electronic structure of diatomic molecules. VII.A. Hartree-Fock wavefunctions and energy quantities for the ground states of the second-row hydrides, AH, J. Chem. Phys., 1967, 47, 649. [all data]

Cade, Bader, et al., 1969
Cade, P.E.; Bader, R.F.W.; Henneker, W.H.; Keaveny, I., Molecular charge distributions and chemical binding. IV. The second-row diatomic hydrides AH, J. Chem. Phys., 1969, 50, 5313. [all data]

Meyer and Rosmus, 1975
Meyer, W.; Rosmus, P., PNO-Cl and CEPA studies of electron correlation effects. III. Spectroscopic constants and dipole moment functions for the ground states of the first-row and second-row diatomic hydrides, J. Chem. Phys., 1975, 63, 2356. [all data]


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