Lithium dimer
- Formula: Li2
- Molecular weight: 13.882
- IUPAC Standard InChI: InChI=1S/2Li
- IUPAC Standard InChIKey: SMBQBQBNOXIFSF-UHFFFAOYSA-N
- CAS Registry Number: 14452-59-6
- Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
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Gas phase thermochemistry data
Go To: Top, Gas phase ion energetics data, Constants of diatomic molecules, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°gas | 51.601 | kcal/mol | Review | Chase, 1998 | Data last reviewed in December, 1983 |
| Quantity | Value | Units | Method | Reference | Comment |
| S°gas,1 bar | 47.087 | cal/mol*K | Review | Chase, 1998 | Data last reviewed in December, 1983 |
Gas Phase Heat Capacity (Shomate Equation)
Cp° = A + B*t + C*t2 + D*t3 +
E/t2
H° − H°298.15= A*t + B*t2/2 +
C*t3/3 + D*t4/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t2/2 + D*t3/3 −
E/(2*t2) + G
Cp = heat capacity (cal/mol*K)
H° = standard enthalpy (kcal/mol)
S° = standard entropy (cal/mol*K)
t = temperature (K) / 1000.
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| Temperature (K) | 298. to 2600. | 2600. to 6000. |
|---|---|---|
| A | 6.834370 | -125.3640 |
| B | 5.741511 | 60.65349 |
| C | -4.139272 | -9.075091 |
| D | 0.832284 | 0.439550 |
| E | 0.041313 | 201.8270 |
| F | 49.48081 | 318.6131 |
| G | 54.05490 | 71.51080 |
| H | 51.60141 | 51.60141 |
| Reference | Chase, 1998 | Chase, 1998 |
| Comment | Data last reviewed in December, 1983 | Data last reviewed in December, 1983 |
Gas phase ion energetics data
Go To: Top, Gas phase thermochemistry data, Constants of diatomic molecules, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias
Data compiled as indicated in comments:
LL - Sharon G. Lias and Joel F. Liebman
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| IE (evaluated) | 5.1127 ± 0.0003 | eV | N/A | N/A | L |
| Quantity | Value | Units | Method | Reference | Comment |
| Proton affinity (review) | 277.7 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
| Quantity | Value | Units | Method | Reference | Comment |
| Gas basicity | 270.82 | kcal/mol | N/A | Hunter and Lias, 1998 | HL |
Ionization energy determinations
| IE (eV) | Method | Reference | Comment |
|---|---|---|---|
| 4.73 ± 0.05 | PI | Dugourd, Rayane, et al., 1992 | LL |
| 5.1127 ± 0.0003 | S | McGeogh and Schlier, 1983 | LBLHLM |
| 5.14 | PI | Eisel and Demtroder, 1982 | LBLHLM |
| 5.0 ± 0.3 | EI | N/A | LLK |
| 5.00 | EVAL | Huber and Herzberg, 1979 | LLK |
| 5.174 ± 0.013 | PI | Mathur, Rothe, et al., 1978 | LLK |
| 5.0 | EI | Zmbov, Wu, et al., 1977 | LLK |
| 4.9 ± 0.1 | EI | N/A | LLK |
| 4.9 ± 0.1 | EI | Ihle and Wu, 1975 | LLK |
| 4.9 ± 0.1 | EI | Emel'yanov, Peredvigina, et al., 1971 | LLK |
| 5.2 ± 0.1 | PI | Foster, Leckenby, et al., 1969 | RDSH |
| 5.0 ± 0.1 | S | Velasco, 1960 | RDSH |
Constants of diatomic molecules
Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, References, Notes
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 March, 1977
| Symbol | Meaning |
|---|---|
| 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) |
| State | Te | ωe | ωexe | ωeye | Be | αe | γe | De | βe | re | Trans. | ν00 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Fragments of other absorption band systems in the ultraviiolet. REFS 5 | ||||||||||||
| D 1Πu | (34518) 1 | [201.68] 1 Z | 0.4628 2 | 0.0073 | 11.4E-6 | 3.222 | D ← X R | 34443.58 1 Z | ||||
| ↳Barrow, Travis, et al., 1960; Mercier, Rico, et al., 1969 | ||||||||||||
| C 1Πu | 30550.6 | 237.9 Z | 3.35 | 0.064 | 0.5075 3 | 0.00973 4 | 0.000154 | 9E-6 | 3.077 | C ← X R | 30493.6 Z | |
| ↳Vance and Huffman, 1935; Sinha, 1948; Barrow, Travis, et al., 1960; Velasco, 1960; Rico, 1969 | ||||||||||||
| B 1Πu | 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 ↔ 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 | ||||||||||||
| State | Te | ωe | ωexe | ωeye | Be | αe | γe | De | βe | re | Trans. | ν00 |
| A 1Σu+ | 14068.35 | 255.47 Z | 1.582 | .0025 | 0.49750 3 | 0.00540 | 7.54E-6 8 | 3.1079 | A ← X 7 R | 14020.63 Z | ||
| ↳Almy and Irwin, 1936; missing citation | ||||||||||||
| a 3Σu+ | Not observed; predicted potential minimum of ~300 cm-1 at 4.3Å Kutzelnigg, Staemmler, et al., 1972. | |||||||||||
| X 1Σg+ | 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 | ||||||||||||
Notes
| 1 | Vibrational numbering uncertain. |
| 2 | Rotational constants from Q branches only; see also 1. |
| 3 | missing note |
| 4 | Rotational constants from Q branches only; Velasco, 1960 gives B(R,P) - B(Q) = 0.0024 Velasco, 1960. |
| 5 | Vibrational 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 1Πu 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 . |
| 6 | Slightly different constants in Velasco, Ennen, et al., 1973; Λ-type doubling Δvef ~ +0.00016J(J+1). |
| 7 | The B-X and A-X systems of 6Li2 have been analyzed by Velasco and Morales, 1973 and Velasco and Rivero, 1972, respectively. |
| 8 | He = +1.23E-10. |
| 9 | weze = -0.000636; from the B→X 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. |
| 11 | He = +1.54E-10. See also 10. |
| 12 | Mol. beam magn. Reson. 16 |
| 13 | Value 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. |
| 14 | Average 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. |
| 15 | RKR potential curves Krupenie, Mason, et al., 1963. |
| 16 | gJ = 0.10797 μN Brooks, Anderson, et al., 1963. Li nuclear electric quadrupole coupling constant Logan, Cote, et al., 1952. |
| 17 | D00(Li2) + I.P.(Li) - I. P.(Li2). |
| 18 | From D00(Li2) and the electron affinities of Li2 and Li. |
| 19 | Theoretical 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. |
References
Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Constants of diatomic molecules, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Chase, 1998
Chase, M.W., Jr.,
NIST-JANAF Themochemical Tables, Fourth Edition,
J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]
Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G.,
Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update,
J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018
. [all data]
Dugourd, Rayane, et al., 1992
Dugourd, P.; Rayane, D.; Labastie, P.; Vezin, B.; Chevaleyre, J.; Broyer, M.,
Measurements of lithium cluster ionization potentials,
Chem. Phys. Lett., 1992, 197, 433. [all data]
McGeogh and Schlier, 1983
McGeogh, M.W.; Schlier, R.E.,
Autoionizing Rydberg states of the Li2 molecule: Molecular constants for Li2+,
Chem. Phys. Lett., 1983, 99, 347. [all data]
Eisel and Demtroder, 1982
Eisel, D.; Demtroder, W.,
Accurate ionization potential of Li2 from resonant two-photon ionization,
Chem. Phys. Lett., 1982, 88, 481. [all data]
Huber and Herzberg, 1979
Huber, K.P.; Herzberg, G.,
Molecular Spectra and Molecular Structure. IV. Constants of Diatomic Molecules,, Van Nostrand Reinhold Co., 1979, ,1. [all data]
Mathur, Rothe, et al., 1978
Mathur, B.P.; Rothe, E.W.; Reck, G.P.; Lightman, A.J.,
Two-photon ionization of Li2: isotopic separation and determination of IP(Li2) and De (Li2+),
Chem. Phys. Lett., 1978, 56, 336. [all data]
Zmbov, Wu, et al., 1977
Zmbov, K.F.; Wu, C.H.; Ihle, H.R.,
A mass spectrometric study of heteronuclear diatomic alkali metal molecules. Dissociation energies ionization potentials of NaLi, KLi, NaK,
J. Chem. Phys., 1977, 67, 4603. [all data]
Ihle and Wu, 1975
Ihle, H.R.; Wu, C.H.,
Mass spectrometric determination of the ionization potential and dissociation energy of LiD,
J. Chem. Phys., 1975, 63, 1605. [all data]
Emel'yanov, Peredvigina, et al., 1971
Emel'yanov, A.M.; Peredvigina, V.A.; Gorokhov, L.N.,
Ionization potentials of Li2 and Na2 molecules and the dissociation energy of Li2+ and Na2+ ions,
Teplofiz. Vysokikh Temperatur, 1971, 9, 190, In original 164. [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, 1960
Velasco, R.,
Espectro ultravioleta de la molecula Li2,
An. R. Soc. Esp. Fis. Quim., 1960, 175. [all data]
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]
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 C1πµ - X1Σ+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 B1Πu 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 B1Πu potential energy curve for Li2,
J. Chem. Phys., 1977, 66, 1135. [all data]
Velasco, Ennen, et al., 1973
Velasco, R.; Ennen, G.; Ottinger, Ch.,
Λ splitting in vibrationally excited Li2(B1Πu),
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]
Velasco, 1973
Velasco, R.,
Productos de disociacion de las series 1Π 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]
Notes
Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Constants of diatomic molecules, References
- Symbols used in this document:
IE (evaluated) Recommended ionization energy S°gas,1 bar Entropy of gas at standard conditions (1 bar) ΔfH°gas Enthalpy of formation of gas at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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