Hydrogen anion

Gas phase thermochemistry data

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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
S°gas,1 bar34.357cal/mol*KReviewChase, 1998Data last reviewed in September, 1977

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 November, 1976

Symbols used in the table of constants
SymbolMeaning
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 H2-
StateTeωeωexeωeyeBeαeγeDeβereTrans.ν00
A comprehensive review of resonances in electron impact on H2, HD, and D2 has been published by Schulz, 1973 and contains references to earlier literature.
G  (2260)         1 15.07 eV 2
↳Schulz, 1973; Schowengerdt and Golden, 1975
F  2420 40        1 13.63 eV 2
↳Schulz, 1973; Schowengerdt and Golden, 1975
D 2Σg+ 1sσ2pπ2  2540 53  [34.5] 3     0.97 4 5 11.32 eV 2
↳Comer and Read, 1971; Schulz, 1973; Spence, 1974; Chang, 1975
StateTeωeωexeωeyeBeαeγeDeβereTrans.ν00
C (2Δg 1sσ2pπ2) () 6 2540 42       1.03 4 11.19 5 11.19 eV 2
↳Comer and Read, 1971; Schulz, 1973; Spence, 1974; Chang, 1975
B 2Σg+ (1sσ2pσ2) () 7 (1530) 40       1.18 4 5 10.93 eV 2
↳Comer and Read, 1971; Schulz, 1973
A 2Σg+ 8            ~10 eV 2
↳Schulz, 1973
X 2Σu+1sσ22pσSlightly bound state (D00 ~ 1-2 eV). 9
↳Schulz, 1973

Notes

1Two progressions of resonances (series "f" and "g") proceeding across the ionization threshold of H2+. Higher members correlate with structure previously observed in photoionization of H2.
2Energies in eV above X 1Σg+(v=0) of H2, all obtained as resonances in electron scattering experiments. The value for B 2Σg+ is extrapolated from v=2.
3From resolved rotational structure of the resonances Comer and Read, 1971.
4From a fit of calculated to observed excitation cross sections Comer and Read, 1971; for D 2Σg+ in good agreement with the value obtained from the observed rotational structure.
5The progressions of resonances attributed to B, C, D are normally referred to as series "b", "c", "a", respectively.
6Assignment according to Chang, 1975; Comer and Read, 1971 favor 1sσ2sσ2pπ, 2Πu.
7Possible parent state B 1Σu+.
8Repulsive curve, having unstable b 3Σu+ state of H2 as its parent state. Observed in dissociative attachment experiments.
9The potential function is well defined only outside the potential well of H2 [see, however, Eliezer, Taylor, et al., 1967]; its asymptote lies 0.75421 eV below that of H2 X 1Σg+. The lifetime against preionization is estimated to be 10-15 s corresponding to a width of l eV. The ground state of H2- causes a broad resonance in the scattering of low energy electrons by H2 and shows up both in the formation of H- by dissociative attachment and in the vibrational excitation of H2.

References

Go To: Top, Gas phase thermochemistry 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]

Schulz, 1973
Schulz, G.J., Resonances in electron impact on diatomic molecules, Rev. Mod. Phys., 1973, 45, 423. [all data]

Schowengerdt and Golden, 1975
Schowengerdt, F.D.; Golden, D.E., Structures in the electron transmission spectrum of H2 near the H2+ threshold, Phys. Rev. A: Gen. Phys., 1975, 11, 160. [all data]

Comer and Read, 1971
Comer, J.; Read, F.H., Potential curves and symmetries of some resonant states of H2-, J. Phys. B:, 1971, 4, 368. [all data]

Spence, 1974
Spence, D., Core-excited resonances in hydrogen, J. Phys. B:, 1974, 7, 87. [all data]

Chang, 1975
Chang, E.S., New interpretation of resonances in H2-, Phys. Rev. A: Gen. Phys., 1975, 12, 2399. [all data]

Eliezer, Taylor, et al., 1967
Eliezer, I.; Taylor, H.S.; Williams, J.K., Jr., Resonant states of H2-, J. Chem. Phys., 1967, 47, 2165. [all data]

Notes

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