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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)K127I+
D (1/2) (143700) 1 2           
C (3/2,1/2) 140800 1 2           
A (1/2) 7900 1 3           
X (3/2,1/2) 0 1 3           


1From band maxima of the photoelectron spectrum Potts, Williams, et al., 1974, missing citation.
2Removal of an electron from the metal 3p shell.
3Removal of an electron from the halogen 5p shell.
4Thermochemical value Brewer and Brackett, 1961; flame photometry Bulewicz, Phillips, et al., 1961 gives 3.49 eV. Earlier spectroscopic estimates were 3.31 eV Levi, 1934 and leq 3.47 eV Barrow and Caunt, 1953.
5Adiabatic potential from the photoelectron spectrum Potts, Williams, et al., 1974, not corrected for thermal population of ground state vibrational levels; band maximum (vertical potential) at 7.68 eV.
6Absorption cross sections Davidovits and Brodhead, 1967. A preliminary measurement of the photodissociation product anisotropy by photofragment spectroscopy at 28800 cm-1 Ormerod, Powers, et al., 1974 indicates strong contributions from perpendicular transitions.
7Photodissociation produces K(4p 2P); similarly, photodissociation at 52600 cm-1 leads to K(5p 2P) Earl and Herm, 1974.
8A differential scattering experiment investigating the collisional depolarization of polarized K atoms missing citation leads to the conclusion that J,J coupling would provide the most adequate description of these states.
9The actual onset and cutoff wavelengths depend on the experimental conditions: a beam-gas arrangement Oldenborg, Gole, et al., 1974 or flames Levi, 1934, Kaufmann, Kinsey, et al., 1974.
10From the microwave results by use of Dunham's theory.
11Quadrupole hyperfine structure Tiemann, Ali, et al., 1973. The dipole moment muel = 10.82 D Story and Hebert, 1976 was measured by the electric deflection method Story and Hebert, 1976; see also Rodebush, Murray, et al., 1936.
12From D00(KI) + I.P.(K) - I.P.(KI); Potts, Williams, et al., 1974, give 0.37 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]

Ormerod, Powers, et al., 1974
Ormerod, R.C.; Powers, T.R.; Rose, T.L., Molecular-beam photodissociation studies of alkali iodides, J. Chem. Phys., 1974, 60, 5109. [all data]

Earl and Herm, 1974
Earl, B.L.; Herm, R.R., Photodissociation of NaBr, Nal, and Kl vapors and collisional quenching of Na* (32P), K* (42P), and K* (52P) by foreign gases, J. Chem. Phys., 1974, 60, 4568. [all data]

Oldenborg, Gole, et al., 1974
Oldenborg, R.C.; Gole, J.L.; Zare, R.N., Chemiluminescent spectra of alkali-halogen reactions, J. Chem. Phys., 1974, 60, 4032. [all data]

Kaufmann, Kinsey, et al., 1974
Kaufmann, K.J.; Kinsey, J.L.; Palmer, H.B.; Tewarson, A., Potassium iodide chemiluminescence in diffusion flames and the Kl upper-state potential, J. Chem. Phys., 1974, 60, 4023. [all data]

Tiemann, Ali, et al., 1973
Tiemann, E.; Ali, H.El.; Hoeft, J.; Torring, T., Hyperfeinstruktur von KJ, Z. Naturforsch. A, 1973, 28, 1058. [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]

Rodebush, Murray, et al., 1936
Rodebush, W.H.; Murray, L.A., Jr.; Bixler, M.E., The dipole moments of the alkali halides, J. Chem. Phys., 1936, 4, 372. [all data]


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