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Lithium dimer

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: K.P. Huber and G. 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 7Li2
Fragments of other absorption band systems in the ultraviiolet. REFS 5
D 1Piu (34518) 1 [201.68] 1 Z   0.4628 2 0.0073  11.4E-6  3.222 D larrow X R 34443.58 1 Z
Barrow, Travis, et al., 1960; Mercier, Rico, et al., 1969
C 1Piu 30550.6 237.9 Z 3.35 0.064 0.5075 3 0.00973 4 0.000154 9E-6  3.077 C larrow X R 30493.6 Z
Vance and Huffman, 1935; Sinha, 1948; Barrow, Travis, et al., 1960; Velasco, 1960; Rico, 1969
B 1Piu 20436.01 270.12 Z 2.673 5 -0.0825 0.5577 6 3 0.0085 -0.00014 9.45E-6 0.14E-6 2.935 B lrarrow X 7 R 20395.32 Z
missing citation; Loomis and Nusbaum, 1931; McKellar, 1933; Velasco, Ottinger, et al., 1969; Ottinger, Velasco, et al., 1970; Velasco, Ruano, et al., 1970; Ottinger and Poppe, 1971
A 1Sigmau+ 14068.35 255.47 Z 1.582 .0025 0.49750 3 0.00540  7.54E-6 8  3.1079 A larrow X 7 R 14020.63 Z
Almy and Irwin, 1936; missing citation
a 3Sigmau+Not observed; predicted potential minimum of ~300 cm-1 at 4.3Å Kutzelnigg, Staemmler, et al., 1972.
X 1Sigmag+ 0 351.43 Z 2.610 9 0.00295 0.67264 3 0.00704 10 -0.00004 9.87E-6 11  2.6729 12  
Logan, Cote, et al., 1952; Brooks, Anderson, et al., 1963


1Vibrational numbering uncertain.
2Rotational constants from Q branches only; see also 1.
3missing note
4Rotational constants from Q branches only; Velasco, 1960 gives B(R,P) - B(Q) = 0.0024 Velasco, 1960.
5Vibrational constants recalculated from band origins (v' = 0....4) of Velasco, Ruano, et al., 1970. Slightly different constants in Loomis and Nusbaum, 1931, from a low-resolution magnetic rotation spectrum including much higher vibrational levels. The B 1Piu state has a potential maximum of ~ 0.09 eV King and Van Vleck, 1939, Velasco, Ottinger, et al., 1969, Olson and Konowalow, 1976; the theoretical calculations of Kahn, Dunning, et al., 1977 predict a barrier of 0.0724 eV at 5.61 .
6Slightly different constants in Velasco, Ennen, et al., 1973; Lambda-type doubling Deltavef ~ +0.00016J(J+1).
7The B-X and A-X systems of 6Li2 have been analyzed by Velasco and Morales, 1973 and Velasco and Rivero, 1972, respectively.
8He = +1.23E-10.
9weze = -0.000636; from the BrarrowX fluorescence spectrum Velasco, Ottinger, et al., 1969, including levels from v=0 to 18.
10(v=0...4) McKellar and Jenkins, 1939. For v>>10 Bv and Dv are better represented by Bv = B10 - 0.0077(v - 10) - 0.00016(v - 10)2 and Dv = D10 + 0.22E-6(v-10) Velasco, Ottinger, et al., 1969.
11He = +1.54E-10. See also 10.
12Mol. beam magn. Reson. 16
13Value recommended by Stwalley, 1976. Extrapolation of the ground state vibrational levels, taking into account the contribution due to long-range forces, gives 8473 cm-1 [1.051 eV, see Stwalley, 1976]. The latest thermochemical value [mass spectrometry missing citation] is 1.11 eV; see also Lewis, 1931, who obtained 1.03 eV using a molecular beam method.
14Average of a photoionization Foster, Leckenby, et al., 1969, and electron impact missing citation, appearance potential (5.15 and 4.86 eV, respectively). The Rydberg series B,C,D... extrapolate to 4.99 eV Velasco, 1973.
15RKR potential curves Krupenie, Mason, et al., 1963.
16gJ = 0.10797 muN Brooks, Anderson, et al., 1963. Li nuclear electric quadrupole coupling constant Logan, Cote, et al., 1952.
17D00(Li2) + I.P.(Li) - I. P.(Li2).
18From D00(Li2) and the electron affinities of Li2 and Li.
19Theoretical electron affinity of Li2 from an ab initio calculation by Dixon, Gole, et al., 1977. A value of 0.90 eV was computed earlier by Andersen and Simons, 1976, but see Dixon, Gole, et al., 1977.


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

Barrow, Travis, et al., 1960
Barrow, R.F.; Travis, N.; Wright, C.V., Excited electronic states of lithium and sodium molecules, Nature, 1960, 187, 141. [all data]

Mercier, Rico, et al., 1969
Mercier, J.L.; Rico, F.R.; Velasco, R., Rotational analysis of some ultraviolet bands of the 7Li2 molecule, Opt. Pura Apl., 1969, 2, 96. [all data]

Vance and Huffman, 1935
Vance, J.E.; Huffman, J.R., The ultraviolet absorption band of Li2, Phys. Rev., 1935, 47, 215. [all data]

Sinha, 1948
Sinha, S.P., Ultra-violet bands of Li2, Proc. Phys. Soc. London, 1948, 60, 443. [all data]

Velasco, 1960
Velasco, R., Espectro ultravioleta de la molecula Li2, An. R. Soc. Esp. Fis. Quim., 1960, 175. [all data]

Rico, 1969
Rico, F.R., Aplicacion de los ordenadores electronicos al estudio de los espectros de absorcion de moleculas diatomicas. I. Calculo de las constantes vibracionales y rotacionales del sistema C1«pi»µ - X1«SIGMA»+g de la molecula de litio, Opt. Pura Apl., 1969, 2, 1, 33-42. [all data]

Loomis and Nusbaum, 1931
Loomis, F.W.; Nusbaum, R.E., The magnetic rotation spectrum and heat of dissociation of the lithium molecule, Phys. Rev., 1931, 38, 1447. [all data]

McKellar, 1933
McKellar, A., Mass ratio of the lithium isotopes from the spectrum of Li2, Phys. Rev., 1933, 44, 155. [all data]

Velasco, Ottinger, et al., 1969
Velasco, R.; Ottinger, Ch.; Zare, R.N., Dissociation energy of Li2 from laser-excited fluorescence, J. Chem. Phys., 1969, 51, 5522. [all data]

Ottinger, Velasco, et al., 1970
Ottinger, Ch.; Velasco, R.; Zare, R.N., Some propensity rules in collision-induced rotational quantum jumps, J. Chem. Phys., 1970, 52, 1636. [all data]

Velasco, Ruano, et al., 1970
Velasco, R.; Ruano, O.; Rico, F.R., El sistema B-X de la molecula Li2, Opt. Pura Apl., 1970, 3, 159. [all data]

Ottinger and Poppe, 1971
Ottinger, Ch.; Poppe, D., Collision-induced rotational and vibrational quantum jumps in electronically excited Li2, Chem. Phys. Lett., 1971, 8, 513. [all data]

Almy and Irwin, 1936
Almy, G.M.; Irwin, G.R., Mass ratio of the lithium isotopes from the spectrum of Li2, Phys. Rev., 1936, 49, 72. [all data]

Kutzelnigg, Staemmler, et al., 1972
Kutzelnigg, W.; Staemmler, V.; Gelus, M., Potential curve of the lowest triplet state of Li2, Chem. Phys. Lett., 1972, 13, 496. [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]

King and Van Vleck, 1939
King, G.W.; Van Vleck, J.H., Dipole-dipole resonance forces, Phys. Rev., 1939, 55, 1165. [all data]

Olson and Konowalow, 1976
Olson, M.L.; Konowalow, D.D., The potential energy curve for the B1«PI»u state of Li2, Chem. Phys. Lett., 1976, 39, 2, 281-284. [all data]

Kahn, Dunning, et al., 1977
Kahn, L.R.; Dunning, T.H., Jr.; Winter, N.W.; Goddard, W.A., III, The theoretical determination of the B1«PI»u potential energy curve for Li2, J. Chem. Phys., 1977, 66, 1135. [all data]

Velasco, Ennen, et al., 1973
Velasco, R.; Ennen, G.; Ottinger, Ch., «LAMBDA» splitting in vibrationally excited Li2(B1«PI»u), Opt. Pura Apl., 1973, 6, 11. [all data]

Velasco and Morales, 1973
Velasco, R.; Morales, V., El sistema de bandas B-X en la molecula 6Li2, Opt. Pura Apl., 1973, 6, 52. [all data]

Velasco and Rivero, 1972
Velasco, R.; Rivero, F., El sistema de bandas A-X en el espectro de la molecula 6Li2, Opt. Pura Apl., 1972, 5, 76. [all data]

McKellar and Jenkins, 1939
McKellar, A.; Jenkins, F.A., The mass ratio of lithium isotopes from the red bands of Li2, Publ. Dom. Astrophys. Obs. Victoria B.C., 1939, 7, 155. [all data]

Stwalley, 1976
Stwalley, W.C., The dissociation energy of 7Li2, J. Chem. Phys., 1976, 65, 2038. [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]

Velasco, 1973
Velasco, R., Productos de disociacion de las series 1«PI» de Li2 Y Na2, Opt. Pura Apl., 1973, 6, 16. [all data]

Krupenie, Mason, et al., 1963
Krupenie, P.H.; Mason, E.A.; Vanderslice, J.T., Interaction energies and transport coefficients of Li+H and O+H gas mixtures at high temperatures, J. Chem. Phys., 1963, 39, 2399. [all data]

Dixon, Gole, et al., 1977
Dixon, D.A.; Gole, J.L.; Jordan, K.D., Ab initio study of the electronic structure of Li2-, J. Chem. Phys., 1977, 66, 567. [all data]

Andersen and Simons, 1976
Andersen, E.; Simons, J., A calculation of the electron affinity of the lithium molecule, J. Chem. Phys., 1976, 64, 4548. [all data]


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