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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 July, 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 (85)Rb(35)Cl+
(D) 108600 1 2           
106900 1 2           
(C) (102000) 2           
100300 1 2           
X 0 1 3           


1From maxima of the photoelectron spectrum Potts, Williams, et al., 1974, missing citation; the halogen 3p spectrum is unresolved. The complexity of the metal 4p photoelectron spectrum is tentatively attributed to configuration interaction in RbBr. See ref 12 of RbBr.
2Ionization from the metal 4p shell.
3Ionization from the halogen 3p shell.
4Thermochemical value Brewer and Brackett, 1961; flame photometric value 4.40 eV Bulewicz, Phillips, et al., 1961.
5Onset of a broad unresolved photoelectron peak with maximum at 8.74 eV Goodman, Allen, et al., 1974, Potts, Williams, et al., 1974.
6Additional peaks in the electron energy loss spectrum at 7.8, 15.5, 19.0, 23.0 eV Geiger and Pfeiffer, 1968. Davidovits and Brodhead, 1967 give absorption cross sections from 34000 to 50000 cm-1.
7There is no conclusive evidence yet for the identity of the upper states observed in the absorption and emission spectra.
8From the IR spectrum Rice and Klemperer, 1957. From the rotational constants Clouser and Gordy, 1964 calculate omegae = 233.34, omegaexe = 0.856.
9eqQ(85Rb) = -52.675 + 0.38v MHz v=0,1,2 Trischka and Braunstein, 1954 eqQ(35Cl) = +0.774 - 0.155v MHz v=0,1,2 Trischka and Braunstein, 1954; for constants of 87Rb35Cl see Bolef and Zeiger, 1952, Trischka and Braunstein, 1954.
10muel[D] = 10.483 + 0.054(v+1/2), v = 0,1,2.
11gJ = (-)0.0183 muN.
12From D00(RbCl) and the ionization potentials of Rb and RbCl.


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

Potts, Williams, et al., 1974
Potts, A.W.; Williams, T.A.; Price, W.C., Photoelectron spectra and electronic structure of diatomic alkali halides, Proc. Roy. Soc. London A, 1974, 341, 147. [all data]

Brewer and Brackett, 1961
Brewer, L.; Brackett, E., The dissociation energies of gaseous alkali halides, Chem. Rev., 1961, 61, 425. [all data]

Bulewicz, Phillips, et al., 1961
Bulewicz, E.M.; Phillips, L.F.; Sugden, T.M., Determination of dissociation constants and heats of formation of simple molecules by flame photometry. Part 8. Stabilities of the gaseous diatomic halides of certain metals, Trans. Faraday Soc., 1961, 57, 921. [all data]

Goodman, Allen, et al., 1974
Goodman, T.D.; Allen, J.D., Jr.; Cusachs, L.C.; Schweitzer, G.K., The photoelectron spectra of gaseous alkali halides, J. Electron Spectrosc. Relat. Phenom., 1974, 3, 289. [all data]

Geiger and Pfeiffer, 1968
Geiger, J.; Pfeiffer, H.-C., Untersuchung der Anregung innerer Elektronen von Alkalihalogenidmolekulen im Energieverlustspektrum von 25 keV-Elektronen, Z. Phys., 1968, 208, 105. [all data]

Davidovits and Brodhead, 1967
Davidovits, P.; Brodhead, D.C., Ultraviolet absorption cross sections for the alkali halide vapors, J. Chem. Phys., 1967, 46, 2968. [all data]

Rice and Klemperer, 1957
Rice, S.A.; Klemperer, W., Spectra of the alkali halides. II. The infrared spectra of the sodium and potassium halides, RbCl, and CsCl, J. Chem. Phys., 1957, 27, 573. [all data]

Clouser and Gordy, 1964
Clouser, P.L.; Gordy, W., Millimeter-wave molecular-beam spectroscopy: alkali chlorides, Phys. Rev., 1964, 134, 863. [all data]

Trischka and Braunstein, 1954
Trischka, J.W.; Braunstein, R., Rotational spectra of RbCl by the molecular beam electric resonance method, Phys. Rev., 1954, 96, 968. [all data]

Bolef and Zeiger, 1952
Bolef, D.I.; Zeiger, H.J., Molecular beam magnetic resonance spectra of Rb87F and Rb87Cl at zero field, Phys. Rev., 1952, 85, 799. [all data]


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