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Beryllium chloride

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 September, 1976

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 9Be35Cl
R shaded emission bands in the region 37900 - 38300 cm-1 Novikov and Tunitskii, 1960 are due to AlCl. Unidentified system (nue = 18686, omegae'=540, omegae"=552 cm-1) in emission Parker, 1934; assignment to BeCl not confirmed.
B 2Sigma+ (48773) [952.5] Z 1  0.7751 2 0.0043  [3.0E-06] 3  1.7422 B rarrow X V 48827.6 Z
missing citation; missing citation
A 2Pir 27992.0 822.11 Z 5.24  0.7094 2 0.0068  0.0000023  1.8211 A lrarrow X R 27979.63
missing citation; missing citation; missing citation
X 2Sigma+ 0 846.7 Z 4.85  0.7285 0.0069  0.0000025  1.7971  


1A very weak head at 48502.7 cm-1 has tentatively been identified as 2-3 band; DeltaG'(3/2)=1212.7 cm-1.
2The Lambda-type doubling in the 1/2 [Deltanuef(v=0) ~ -0.011(J+1/2)] and 3/2 components does not conform with the "pure precession" pattern frequently observed in regular 2Pi states; see Colin, Carleer, et al., 1972.
4values for D00 obtained by various methods have been summarized in Farber and Srivastava, 1974, all being close to 4.51 eV and substantially higher than a mass-spectrometric value of 3.99 eV Hildenbrand and Theard, 1969. The interpretation Carleer, Burtin, et al., 1977 of an inverse predissociation assumed to be responsible for the strikingly high intensity of B rarrow X bands with v'=1 suggests an even lower value of 3.45 eV.


Go To: Top, Constants of diatomic molecules, Notes

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

Novikov and Tunitskii, 1960
Novikov, M.M.; Tunitskii, L.N., Vibrational constants and dissociation energy of the BeCl molecule, Opt. Spectrosc. Engl. Transl., 1960, 8, 396. [all data]

Parker, 1934
Parker, A.E., Vibrational analysis of BaCl and BeCl bands, Phys. Rev., 1934, 45, 752. [all data]

Colin, Carleer, et al., 1972
Colin, R.; Carleer, M.; Prevot, F., Rotational analysis of the A2«PI»-X2«SIGMA»+ band system of the BeCl molecule, Can. J. Phys., 1972, 50, 171. [all data]

Farber and Srivastava, 1974
Farber, M.; Srivastava, R.D., Dissociation energies of BeF and BeCl and the heat of formation of BeClF, J. Chem. Soc. Faraday Trans. 1, 1974, 70, 1581. [all data]

Hildenbrand and Theard, 1969
Hildenbrand, D.L.; Theard, L.P., Mass spectrometric measurement of the dissociation energies of BeCi and BeCl2, J. Chem. Phys., 1969, 50, 5350. [all data]

Carleer, Burtin, et al., 1977
Carleer, M.; Burtin, B.; Colin, R., A new predissociated 2«SIGMA»+ state of the BeCl molecule, Can. J. Phys., 1977, 55, 582-588. [all data]


Go To: Top, Constants of diatomic molecules, References