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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 March, 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 23Na(35)Cl+
A (1/2) 3710 1 2           
X (3/2,1/2) 0 1 2           


1From band maxima in the photoelectron spectrum Goodman, Allen, et al., 1974, Potts, Williams, et al., 1974.
2Removal of an electron from the halogen 3p shell of Na+ Cl-.
3Thermochemical value [ Brewer and Brackett, 1961,21, flame photometry Gurvich and Veits, 1957, Gurvich and Veits, 1958, Bulewicz, Phillips, et al., 1961].
4Adiabatic potential from the onset of a broad photoelectron peak with maximum at 9.34 eV Potts, Williams, et al., 1974; not corrected for thermal population of ground state levels.
5Also observed in the electron energy loss spectrum Geiger and Pfeiffer, 1968 which has additional peaks at 7.1, 9.6, (20.5), 31.5 eV.
6UV absorption cross sections Davidovits and Brodhead, 1967.
7From the IR spectrum Rice and Klemperer, 1957.
8He = -3.40E-14.
9For IR spectrum of matrix isolated sodium chloride see Ismail, Hauge, et al., 1975.
10muel[D] = 8.97141 + 0.05940(v+1/2) + 0.00025(v+1/2)2, vleq3 Hebert, Lovas, et al., 1968, de Leeuw, van Wachem, et al., 1970. For electric quadrupole coupling constants and their dependence on v see Cederberg and Miller, 1969, de Leeuw, van Wachem, et al., 1970; earlier results by the magnetic resonance method.
11From D00(NaCl)+I.P.(Na)-I.P.(NaCl); Potts, Williams, et al., 1974 suggest 0.33 eV using a corrected value for I.P.(NaCl).
12From D00(NaCl) and the electron affinities of NaCl and Cl.
13Estimated electron affinity Jordan, 1976.


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

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]

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]

Gurvich and Veits, 1957
Gurvich, L.V.; Veits, I.V., Spectroscopic investigation of the equilibrium of the reaction NaCl = Na + Cl in a hydrogen-chlorine flame and the energy of dissociation of NaCl, Dokl. Phys. Chem. Engl. Transl., 1957, 116, 639-640. [all data]

Gurvich and Veits, 1958
Gurvich, L.V.; Veits, I.V., Determination of molecular dissociation energies from flame reaction equilibrium studies, Bull. Acad. Sci. USSR, Phys. Ser. Engl. Transl., 1958, 22, 670-673. [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]

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]

Ismail, Hauge, et al., 1975
Ismail, Z.K.; Hauge, R.H.; Margrave, J.L., Infrared studies of matrix isolated sodium and potassium chloride and cyanide dimers, J. Mol. Spectrosc., 1975, 54, 402. [all data]

Hebert, Lovas, et al., 1968
Hebert, A.J.; Lovas, F.J.; Melendres, C.A.; Hollowell, C.D.; Story, T.L., Jr.; Street, K., Jr., Dipole moments of some alkali halide molecules by the molecular beam electric resonance method, J. Chem. Phys., 1968, 48, 2824. [all data]

de Leeuw, van Wachem, et al., 1970
de Leeuw, F.H.; van Wachem, R.; Dymanus, A., Radio-frequency spectra of NaCl by the molecular-beam electric resonance method, J. Chem. Phys., 1970, 53, 981. [all data]

Cederberg and Miller, 1969
Cederberg, J.W.; Miller, C.E., Hyperfine spectrum of NaCl by molecular-beam electric resonance, J. Chem. Phys., 1969, 50, 3547. [all data]

Jordan, 1976
Jordan, K.D., Correlation between molecular electron affinities and dipole moments, J. Chem. Phys., 1976, 65, 1214. [all data]


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