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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(79)Br+
(D) 116200 1           
114400 2 1           
111800 1           
(109700) 1           
(C) 106700 2 1           
(104300) 1           
A (1/2) 3630 2 3           
X (3/2,1/2) 0 2 3           


1Ionization from the metal 4p shell. 11
2From the maxima of the photoelectron peaks Potts, Williams, et al., 1974, missing citation; see also Goodman, Allen, et al., 1974.
3Ionization from the halogen 4p shell.
4Thermochemical value Brewer and Brackett, 1961; 3.98 eV by flame photometry Bulewicz, Phillips, et al., 1961.
5Onset of the photoelectron spectrum Potts, Williams, et al., 1974, vertical transition at 8.17 eV.
6Also observed in the electron energy loss spectrum Geiger and Pfeiffer, 1968, additional peaks at 7.4, 16.3, 19.8 eV. Davidovits and Brodhead, 1967 give absorption cross sections from 30300 to 50000 cm-1.
7There is no conclusive evidence yet for the identity of the upper states observed in the absorption and emission spectra.
8Calculated from the rotational constants Rusk and Gordy, 1962.
9eqQ(85Rb) = -47.20 + 0.28(v+1/2) MHz Tiemann, Holzer, et al., 1977; eqQ(79Br) = +3.08 + 0.75(v+1/2) MHz Tiemann, Holzer, et al., 1977 muel = 10.86 D [molecular beam electric deflection Story and Hebert, 1976].
10From D00(RbBr), I.P.(Rb), and I.P.(RbBr).
11The complexity of the metal 4p photoelectron spectrum is tentatively attributed to configuration interaction missing citation.


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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]

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]

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]

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]

Rusk and Gordy, 1962
Rusk, J.R.; Gordy, W., Millimeter wave molecular beam spectroscopy: alkali bromides and iodides, Phys. Rev., 1962, 127, 817. [all data]

Tiemann, Holzer, et al., 1977
Tiemann, E.; Holzer, B.; Hoeft, J., Hyperfeinstruktur des RbBr, Z. Naturforsch. A, 1977, 32, 123. [all data]

Story and Hebert, 1976
Story, T.L., Jr.; Hebert, A.J., Dipole moments of KI, RbBr, RbI, CsBr, and CsI by the electric deflection method, J. Chem. Phys., 1976, 64, 855. [all data]


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