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 39K2
Unidentified diffuse emission bands, 17460 - 17840 cm-1.
Rebbeck and Vaughan, 1971
Diffuse bands close to lines of the principal series of K; fragments of additional systems.
Kuhn, 1932; Chakraborti, 1937; Okuda, 1936
G 28091 64.90 1 H 0.55        G ← X R 28077 H
Yoshinaga, 1937
F 27571 62.29 1 H 0.24        F ← X R 27556 H
Yoshinaga, 1937
E 26494.0 61.8 2 H 0.28        E ← X R 26478.9 H
Yoshinaga, 1937; Sinha, 1950
D 24627.7 61.60 H 0.90 3 0.0010       D ← X R 24612.3 H
Sinha, 1948
C 1Πu 22969.43 61.485 Z 0.133  0.04404 0.00011 3E-6   4.433 C ← X R 22954.20 Z
Yamamoto, 1929; Sinha, 1948; Robertson and Barrow, 1961
B 1Πu 15376.74 75.00 0.3876 4 4.366E-3 0.048763 5 0.00024  8.25E-8  4.2125 B 6 ↔ X 7 R 15368.20 Z
Loomis, 1931; Loomis and Nusbaum, 1932; Tango, Link, et al., 1968
A 1Σu+ 11681.9 69.09 H 0.153  8      A ↔ X R 11670.5 H
Crane and Christy, 1930; Sorokin and Lankard, 1971
a 3Σu+Not observed; scattering calculations predict a very shallow potential minimum at ~8.7 Å.
Geittner, 1975
X 1Σg+ 0 92.021 Z 0.2829 9 -2.055E-3 0.056743 0.000165 10  8.63E-8  3.9051 11  
Kusch, Millman, et al., 1939; Logan, Cote, et al., 1952; Brooks, Anderson, et al., 1963


1Analysis by Yoshinaga, 1937; not confirmed by Sinha, 1950.
2Average of the constants obtained by Yoshinaga, 1937, Sinha, 1950.
3ωeze = -0.00030; convergence at 25590.
4ωeze = -0.0001830; vibrational constants for v'≤ 25 from low-resolution magnetic rotation spectra. Higher vibrational levels converge rapidly at 17160 cm-1 above X 1Σg+, v=0. Te is from the analysis of high-resolution laser-induced fluorescence spectra Tango, Link, et al., 1968.
5Recalculated by Tango, Link, et al., 1968, from the data of Loomis, 1931.
6Radiative lifetime τ(v = 6,7,8) = 12.4 ns Tango and Zare, 1970; Baumgartner, Demtroder, et al., 1970 measured 9.7 ns.
7Absorption cross sections Lapp and Harris, 1966.
8A complex magnetic rotation spectrum has been observed which may be due to perturbations of A 1Σu+ by an unidentified 3Π state Carroll, 1937.
9Vibrational and rotational constants from the laser-induced B ≥ X fluorescence spectrum Tango, Link, et al., 1968.
10αv= -7.2E-6(v+1/2)2 + 1.5E-7(v+1/2)3. See 9.
11Mol. beam magn. reson. 14
12From the convergence limit of B 1Πu. Thermochemical value [ Lewis, 1931, recalculated Loomis and Nusbaum, 1932] 0.56 eV.
13Photoionization of K2 Foster, Leckenby, et al., 1969; in agreement with limits (3.57 ≤ I.P. ≤ 4.11 eV) obtained from chemi-ionization thresholds Lee and Mahan, 1965, Williams, 1967, Robertson and Barrow, 1961 estimate 4.09 eV.
14gJ = 0.02163 μN 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 ≤ D00 ≤ 1.27 eV Williams, 1967. Theoretical calculations Bellomonte, Cavaliere, et al., 1974 give l eV.
16Theoretical calculations Bellomonte, Cavaliere, et al., 1974.


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

Rebbeck and Vaughan, 1971
Rebbeck, M.M.; Vaughan, J.M., Unidentified diffuse bands in the spectrum of potassium, J. Phys. B:, 1971, 4, 258. [all data]

Kuhn, 1932
Kuhn, H., Uber spektren von unecht gebundenen molekulen (polarisationsmolekulen) K2, Na2, Cs2 und verbreiterung von absorptionslinien, Z. Phys., 1932, 76, 782. [all data]

Chakraborti, 1937
Chakraborti, B.K., On a new type of absorption bands of potassium vapour, Indian J. Phys., 1937, 10, 155. [all data]

Okuda, 1936
Okuda, T., Narrow continuous band of potassium in the extreme red, Nature (London), 1936, 138, 168. [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]

Sinha, 1948
Sinha, S.P., Blue and ultra-violet bands of K2, Proc. Phys. Soc. London, 1948, 60, 436. [all data]

Yamamoto, 1929
Yamamoto, Revised by Crane and Christy, 1930, 1929, 355. [all data]

Robertson and Barrow, 1961
Robertson, E.W.; Barrow, R.F., Rotational analysis oi the C1πu-X1+g system of K2, and the ionisation potential of K2, Proc. Chem. Soc., 1961, 329. [all data]

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

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]

Crane and Christy, 1930
Crane, W.O.; Christy, A., Vibrational quantum analysis of the potassium infrared absorption bands, Phys. Rev., 1930, 36, 421. [all data]

Sorokin and Lankard, 1971
Sorokin, P.P.; Lankard, J.R., Emission spectra of alkali-metal molecules observed with a heat-pipe discharge tube, J. Chem. Phys., 1971, 55, 3810. [all data]

Geittner, 1975
Geittner, P., Bestimmung der Triplett-Potentialdaten fur das K2-Stossmolekul, Z. Phys., 1975, 272, 359. [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]

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]

Tango and Zare, 1970
Tango, W.J.; Zare, R.N., Radiative lifetime of the B1Πu 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]

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]

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]

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]


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