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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 January, 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 (39)K(35)Cl+
D (1/2) (131500) 1 2           
C (3/2,1/2) 129500 1 2           
A (1/2) 0 1 3           
X (3/2,1/2) 0 1 3           


1From the maxima in the photoelectron spectrum Potts, Williams, et al., 1974, missing citation. The two peaks corresponding to the 2P3/2 and 2P1/2 compoments of normal Cl are not resolved.
2Removal of an electron from the metal 3p shell.
3Removal of an electron from the halogen 3p shell.
4Thermochemical value Brewer and Brackett, 1961, Bulewicz, Phillips, et al., 1961; the analysis of the fluctuation bands gave D00 = 4.39 eV Levi, 1934 (and omega" = 280 Levi, 1934) according to Levi, 1934, or D00 leq 4.66 eV Barrow and Caunt, 1953 (and omega" = 305 Barrow and Caunt, 1953) according to Barrow and Caunt, 1953.
5Adiabatic potential from the photoelectron spectrum of Potts, Williams, et al., 1974, not corrected for thermal population of ground state vibrational levels; the band maximum (vertical potential) is at 8.92 eV.
6UV absorption cross sections Davidovits and Brodhead, 1967. In the electron energy loss spectrum Geiger and Pfeiffer, 1968, there are peaks at 42000, 53000, and 68000 cm-1.
7See CsBr note d. From the emission data Kaufmann, Kinsey, et al., 1974, have derived a tentative potential energy curve for the upper state (see KBr note d); D'e ~450 cm-1.
8From the IR spectrum. The Dunham theory applied to the microwave results gives omegae = 279.80, omegaexe = 1.167.
9IR study of matrix isolated KCl Ismail, Hauge, et al., 1975.
10muel[D] = 10.2391 + 0.05966(v+1/2) + 0.00019(v+1/2)2 missing citation, Hebert, Lovas, et al., 1968; nuclear electric quadrupole and spin-rotation coupling constants missing citation.
11From D00(KCl) + I.P.(K) - I.P.(KCl) Potts, Williams, et al., 1974, give 0.19 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.

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]

Levi, 1934
Levi, Dissertation, Berlin, 1934, 0. [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]

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]

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]

Kaufmann, Kinsey, et al., 1974
Kaufmann, K.J.; Kinsey, J.L.; Palmer, H.B.; Tewarson, A., Chemiluminescent emission spectra and possible upper-state potentials of KCl and KBr, J. Chem. Phys., 1974, 61, 1865. [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]


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