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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 July, 1976

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 19F2+
Ab initio calculations Balint-Kurti, 1971 predict several further stable states. Ground state calc. Ellis, Banyard, et al., 1973.
B (2Sigmag+) 43000 1           
Cornford, Frost, et al., 1971
A 2Piu,i (22755) 2          A rarrow X 3 R 22139
Porter, 1968
22484.8 2 520.4 2 7.30 2        A rarrow X 3 R 22208.8 2 H
Porter, 1968
X 2Pig,i 340 4           
0 1073.3 2 H 9.13 2  1.015 5 0.010    1.322  


1From the photoelectron spectrum; uncertain observation.
2From the R heads in the 3/2-3/2 sub-system. The (arbitrary) lower state vibrational numbering of Porter, 1968 has been reduced by 5 leading to better agreement with the excitation energy of 2.70 eV (21800 cm-1) and the ground state vibrational frequency found by photoelectron spectroscopy Cornford, Frost, et al., 1971, Potts and Price, 1971; see also Gole and Margrave, 1972.
3Bands attributed to this system by Stricker, 1966 are probably all due to F2 (I rarrowF), see Porter, 1968.
4From the photoelectron spectrum Cornford, Frost, et al., 1971. At slightly lower resolution Potts and Price, 1971 find 240 cm-1.
5Revised vibrational numbering, see 2.
6From D00 (F2), I.P.(F2), and I.P.(F).


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

Balint-Kurti, 1971
Balint-Kurti, G.G., Low-lying states of F2+, Mol. Phys., 1971, 22, 681. [all data]

Ellis, Banyard, et al., 1973
Ellis, D.J.; Banyard, K.E.; Tait, A.D.; Dixon, M., Potential energy curves and spectroscopic constants for some diatomic systems, J. Phys. B:, 1973, 6, 233. [all data]

Cornford, Frost, et al., 1971
Cornford, A.B.; Frost, D.C.; McDowell, C.A.; Ragle, J.L.; Stenhouse, I.A., Photoelectron spectra of the halogens, J. Chem. Phys., 1971, 54, 2651. [all data]

Porter, 1968
Porter, T.L., Emission spectrum of molecular fluorine, J. Chem. Phys., 1968, 48, 2071. [all data]

Potts and Price, 1971
Potts, A.W.; Price, W.C., Photoelectron spectra of the halogens and mixed halides ICI and lBr, J. Chem. Soc. Faraday Trans., 1971, 67, 1242. [all data]

Gole and Margrave, 1972
Gole, J.L.; Margrave, J.L., The vacuum ultraviolet spectrum of molecular fluorine, J. Mol. Spectrosc., 1972, 43, 65. [all data]

Stricker, 1966
Stricker, W., Die Bandenemission des F2 und F2+ im Spektralbereich zwischen 4500 und 8500 Å, Z. Naturforsch. A, 1966, 21, 1518. [all data]


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