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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)K2+
No spectrum observed. The formation of K(4p) in (K+,K) collisions has been studied by Aquilanti and Casavecchia, 1976 who have interpreted the magnitude and velocity dependence of the cross section in terms of properties of the potential curves for the lowest exited states of K2+.
X 2Sigmag+ 0 (67) 1        (4.11) 1  


1Theoretical calculations Bellomonte, Cavaliere, et al., 1974.
2From the convergence limit of B 1Piu. Thermochemical value [ Lewis, 1931, recalculated Loomis and Nusbaum, 1932] 0.56 eV.
3Photoionization of K2 Foster, Leckenby, et al., 1969; in agreement with limits (3.57 leq I.P. leq 4.11 eV) obtained from chemi-ionization thresholds Lee and Mahan, 1965, Williams, 1967, Robertson and Barrow, 1961 estimate 4.09 eV.
4Analysis by Yoshinaga, 1937; not confirmed by Sinha, 1950.
5Average of the constants obtained by Yoshinaga, 1937, Sinha, 1950.
6omegaeze = -0.00030; convergence at 25590.
7omegaeze = -0.0001830; vibrational constants for v'leq 25 from low-resolution magnetic rotation spectra. Higher vibrational levels converge rapidly at 17160 cm-1 above X 1Sigmag+, v=0. Te is from the analysis of high-resolution laser-induced fluorescence spectra Tango, Link, et al., 1968.
8Recalculated by Tango, Link, et al., 1968, from the data of Loomis, 1931.
9Radiative lifetime tau(v = 6,7,8) = 12.4 ns Tango and Zare, 1970; Baumgartner, Demtroder, et al., 1970 measured 9.7 ns.
10Absorption cross sections Lapp and Harris, 1966.
11A complex magnetic rotation spectrum has been observed which may be due to perturbations of A 1Sigmau+ by an unidentified 3Pi state Carroll, 1937.
12Vibrational and rotational constants from the laser-induced B geq X fluorescence spectrum Tango, Link, et al., 1968.
13alphav= -7.2E-6(v+1/2)2 + 1.5E-7(v+1/2)3. See 12.
14gJ = 0.02163 muN Brooks, Anderson, et al., 1963. For NMR spectrum and potassium eqQ see Kusch, Millman, et al., 1939, Logan, Cote, et al., 1952.
15From D00(K2) + I.P.(K) - I.P.(K2). The experimentally observed limits (photoionization of potassium vapor, are 0.74 eV leq D00 leq 1.27 eV Williams, 1967. Theoretical calculations Bellomonte, Cavaliere, et al., 1974 give l 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.

Aquilanti and Casavecchia, 1976
Aquilanti, V.; Casavecchia, P., Total inelastic cross sections for potassium ion-atom collisions: oscillations in the velocity dependence and correlation with molecular structure, J. Chem. Phys., 1976, 64, 751. [all data]

Bellomonte, Cavaliere, et al., 1974
Bellomonte, L.; Cavaliere, P.; Ferrante, G., Alkali molecular ion energies and expectation values in a model-potential treatment, J. Chem. Phys., 1974, 61, 3225. [all data]

Lewis, 1931
Lewis, L.C., Die bestimmung des gleichgewichts zwischen den atomen und den molekulen eines alkalidampfes mit einer molekularstrahlmethode, Z. Phys., 1931, 69, 786. [all data]

Loomis and Nusbaum, 1932
Loomis, F.W.; Nusbaum, R.E., Magnetic rotation spectrum and heat of dissociation of the potassium molecule, Phys. Rev., 1932, 39, 89. [all data]

Foster, Leckenby, et al., 1969
Foster, P.J.; Leckenby, R.E.; Robbins, E.J., The ionization potentials of clustered alkali metal atoms, J. Phys. B:, 1969, 2, 478. [all data]

Lee and Mahan, 1965
Lee, Y.-T.; Mahan, B.H., Photosensitized ionization of alkali-metal vapors, J. Chem. Phys., 1965, 42, 2893. [all data]

Williams, 1967
Williams, R.A., Photoionization of potassium vapor, J. Chem. Phys., 1967, 47, 4281. [all data]

Robertson and Barrow, 1961
Robertson, E.W.; Barrow, R.F., Rotational analysis oi the C1«pi»u-X1+g system of K2, and the ionisation potential of K2, Proc. Chem. Soc., 1961, 329. [all data]

Yoshinaga, 1937
Yoshinaga, H., New ultraviolet absorption bands of sodium and potassium molecules, Proc. Phys. Math. Soc. Jpn., 1937, 19, 847. [all data]

Sinha, 1950
Sinha, S.P., Ultra-violet bands of K2, Proc. Phys. Soc. London Sect. A, 1950, 63, 952. [all data]

Tango, Link, et al., 1968
Tango, W.J.; Link, J.K.; Zare, R.N., Spectroscopy of K2 using laser-induced fluorescence, J. Chem. Phys., 1968, 49, 4264. [all data]

Loomis, 1931
Loomis, F.W., Rotational structure of the red bands of potassium, Phys. Rev., 1931, 38, 2153. [all data]

Tango and Zare, 1970
Tango, W.J.; Zare, R.N., Radiative lifetime of the B1«PI»u state of K2, J. Chem. Phys., 1970, 53, 3094. [all data]

Baumgartner, Demtroder, et al., 1970
Baumgartner, G.; Demtroder, W.; Stock, M., Lifetime-measurements of alkali-molecules excited by different laserlines, Z. Phys., 1970, 232, 462. [all data]

Lapp and Harris, 1966
Lapp, M.; Harris, L.P., Absorption cross sections of alkali-vapor molecules: I. Cs2 in the visible. II. K2 in the red, J. Quant. Spectrosc. Radiat. Transfer, 1966, 6, 169. [all data]

Carroll, 1937
Carroll, T., Magnetic rotation spectra of diatomic molecules, Phys. Rev., 1937, 52, 822. [all data]

Brooks, Anderson, et al., 1963
Brooks, R.A.; Anderson, C.H.; Ramsey, N.F., Rotational magnetic moments of diatomic alkalis, Phys. Rev. Lett., 1963, 10, 441. [all data]

Kusch, Millman, et al., 1939
Kusch, P.; Millman, S.; Rabi, I.I., The nuclear magnetic moments of N14, Na23, K39 and Cs133, Phys. Rev., 1939, 55, 1176. [all data]

Logan, Cote, et al., 1952
Logan, R.A.; Cote, R.E.; Kusch, P., The sign of the quadrupole interaction energy in diatomic molecules, Phys. Rev., 1952, 86, 280. [all data]


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