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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 November, 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 133Cs127I+
80000 - 100000 1           
Berkowitz, Dehmer, et al., 1973
A (1/2) (7400) 2           
Berkowitz, Dehmer, et al., 1973; Potts, Williams, et al., 1974
X (3/2,1/2) 0 3           
Berkowitz, Dehmer, et al., 1973; Potts, Williams, et al., 1974


1Two or perhaps three peaks in the 17 - 20 eV region of the photoelectron spectrum are believed to arise from the removal of an electron from the metal 5p shell of Cs+I-.
2From the photoelectron spectrum; removal of an electron from the halogen 5p shell of Cs+I-.
3The 3/2 and 1/2 components of the stronger peak are not resolved.
4Average of a thermochemical value Brewer and Brackett, 1961 and a value obtained from photodissociative ionization of CsI Berkowitz, 1969. See also Bulewicz, Phillips, et al., 1961, Scheer and Fine, 1962.
5From photoionization mass-spectrometry Berkowitz, 1969. The adiabatic ionization potential from photoelectron spectroscopy Berkowitz, Dehmer, et al., 1973, Potts, Williams, et al., 1974 is 7.10 eV; the first and second vertical potentials are 7.54 and 8.46 eV (average values).
6Derived from the rotational constants Honerjager and Tischer, 1974. See also Barrow and Caunt, 1953, Rice and Klemperer, 1957.
7alphav= +4.89E-8(v+1/2)2 + 1.14E-10(v+1/2)3 Honerjager and Tischer, 1974.
8Also higher order constants Honerjager and Tischer, 1974.
9muel = 11.69D Story and Hebert, 1976 (molecular beam electric deflection) Story and Hebert, 1976; eqQ(127I) = -[14.28 + 2.10(v+1/2)] MHz, |eqQ(133Cs)| leq 1 MHz Hoeft, Tiemann, et al., 1972; |gJ| < 0.0036 muN Honerjager and Tischer, 1973.
10From the photoionization data of Berkowitz, 1969. Using 7.10 instead of 7.25 eV for I.P.(CsI) (see 5) would increase this value to 0.36 eV.


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

Berkowitz, Dehmer, et al., 1973
Berkowitz, J.; Dehmer, J.L.; Walker, T.E.H., PES of high-temperature vapors. IV. The cesium halides. Effect of spin-orbit interaction on the photoelectron and mass spectra of the alkali halides, J. Chem. Phys., 1973, 59, 3645. [all data]

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]

Berkowitz, 1969
Berkowitz, J., Photoionization of high-temperature vapors. V. Cesium halides; chemical shift of autoionization, J. Chem. Phys., 1969, 50, 3503. [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]

Scheer and Fine, 1962
Scheer, M.D.; Fine, J., Entropies, heats of sublimation, and dissociation energies of the cesium halides, J. Chem. Phys., 1962, 36, 1647. [all data]

Honerjager and Tischer, 1974
Honerjager, R.; Tischer, R., Mikrowellenrotationsspektren der Molekeln CsF, CsCl, CsBr und CsI, Z. Naturforsch. A, 1974, 29, 819. [all data]

Barrow and Caunt, 1953
Barrow, R.F.; Caunt, A.D., The ultra-violet absorption spectra of some gaseous alkali-metal halides and the dissociation energy of fluorine, Proc. R. Soc. London A, 1953, 219, 120. [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]

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]

Hoeft, Tiemann, et al., 1972
Hoeft, J.; Tiemann, E.; Torring, T., Hyperfeinstruktur von CsJ, Z. Naturforsch. A, 1972, 27, 1017. [all data]

Honerjager and Tischer, 1973
Honerjager, R.; Tischer, R., Hochtemperatur-Mikrowellenspektrometer fur Zeeman-Effekt-Messungen an diamagnetischen Molekeln. gJ - Faktor von TlF, CsF, CsCl, CsBr, CsI und Anistropie der magnetischen suszeptibilitat von TlF, CsF und CsCl, Z. Naturforsch. A, 1973, 28, 458. [all data]


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