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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 June, 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 (79)Br19F+
X2 2Pi1/2 2600 1 750 1          
X1 2Pi3/2 0 750 1          


1From the photoelectron spectrum DeKock, Higginson, et al., 1972.
2From the heats of formation Stull and Prophet, 1971 of BrF and Br2 and the dissociation energies of Br2 and F2. A higher value, 2.71 eV, was suggested Coxon, 1975 on the basis of an assumed 20% failure for the linear Birge-Sponer extrapolation of the ground state.
3From the photoelectron spectrum DeKock, Higginson, et al., 1972; in reasonable agreement with an electron impact appearance potential of 11.8 eV Irsa and Friedman, 1958.
4Fragmentary observations; the constants are very uncertain. See Coxon, 1975.
5Rotational constants recalculated by Calder and Ruedenberg, 1968 from Smith, Tidwell, et al., 1950.
6muel=1.29 D; also values for eqQ(79,81Br). Zeeman effect Ewing, Tigelaar, et al., 1972.
7D00(BrF) + I.P.(Br) - I.P.(BrF).


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

DeKock, Higginson, et al., 1972
DeKock, R.L.; Higginson, B.R.; Lloyd, D.R.; Breeze, A.; Cruickshank, D.W.J.; Armstrong, D.R., Photoelectron spectra of halides. V. Experimental theoretical study of the electronic structures of ClF, ClF3, BrF and BrF3, Mol. Phys., 1972, 24, 1059. [all data]

Stull and Prophet, 1971
Stull, D.R.; Prophet, H., JANAF Thermochemical Tables. Second Edition, Office of SRD (NSRDS-NBS 37), Washington, D.C., 1971, 0. [all data]

Coxon, 1975
Coxon, J.A., Dissociation energies of diatomic halogen fluorides, Chem. Phys. Lett., 1975, 33, 136. [all data]

Irsa and Friedman, 1958
Irsa, A.P.; Friedman, L., Mass spectra of halogen fluorides, J. Inorg. Nucl. Chem., 1958, 6, 77. [all data]

Calder and Ruedenberg, 1968
Calder, G.V.; Ruedenberg, K., Quantitative correlations between rotational and vibrational spectroscopic constants in diatomic molecules, J. Chem. Phys., 1968, 49, 5399. [all data]

Smith, Tidwell, et al., 1950
Smith, D.F.; Tidwell, M.; Williams, D.V.P., The microwave spectrum of bromine monofluoride, Phys. Rev., 1950, 77, 420. [all data]

Ewing, Tigelaar, et al., 1972
Ewing, J.J.; Tigelaar, H.L.; Flygare, W.H., Molecular Zeeman effect, magnetic properties, and electric quadrupole moments in C1F, BrF, C1CN, BrCN, and ICN, J. Chem. Phys., 1972, 56, 1957. [all data]


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