Home Symbol which looks like a small house Up Solid circle with an upward pointer in it

NOTICE: Due to scheduled maintenance at our Gaithersburg campus, this site will not be available from 5:00 pm EDT (21:00 UTC) on Friday October 25 until 5:00 pm (21:00 UTC) on Sunday October 27. We apologize for any inconvenience this outage may cause.


Data at NIST subscription sites:

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.

Constants of diatomic molecules

Go To: Top, 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 August, 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 12C19F
Fragments of additional systems in the absorption spectrum above 50000 cm-1.
Mathews, 1971
C' 2Sigma+     [1.5327] 1   [3.3E-6]  1.223 C' larrow X V 53597.0
Mathews, 1971
D 2Pi 52272.5 2 1803.9 Z 13.0  1.7301 0.0193  6.5E-6  1.1510 D larrow X V 52519.9 3
Mathews, 1971
B 2Deltar 49399.6 4 [1153.34] Z 19.48 H -0.4 1.3206 5 0.0228  4.0E-6  1.3174 B lrarrow X 6 R 49340.1 7 Z
missing citation; Margrave and Wieland, 1953; missing citation
A 2Sigma+ 42692.9 1780.45 Z 30.73  1.7228 8 0.0189 9 -0.0028 [6.80E-6] 10  1.1535 A lrarrow X 11 V 42924.17 12 Z
missing citation; Margrave and Wieland, 1953; Mann, Broida, et al., 1954; Kuzyakov and Tatevskii, 1958; Thrush and Zwolenik, 1963; Porter, Mann, et al., 1965; Mathews, 1971
a 4Sigma- (22000) 13 (1324) 13 (11) 13  (1.302) 13 (0.013) 13      
X 2Pir 0 14 1308.1 Z 11.10 15 0.093 1.4172 16 0.01840 0.00011 6.5E-6  1.2718 17  
Carrington and Howard, 1970


1Line width increases with N. Vibrational numbering uncertain.
2A ~ +0.2 or +6.5.
3By extrapolation from the 1-0,2-0, and 3-0 bands; the 0-0 band was not observed.
4A0= +0.76. The alternative value, A0= +4.48, leads to disagreement between observed and calculated relative line intensities Mathews, 1971.
5Strong perturbations in v=2 Mathews, 1971.
6Radiative lifetime tau(v'=0) = 18.8 ns Hesser and Dressler, 1966, Hesser, 1968; f00(Blarrowx) =0.022 (recalculated for a 2Delta upper state). See also Wentink and Isaacson, 1967.
7J'=3/2 (average of {F1} and F2) relative to J"=1/2 (average of F1 and {F2}). The band centers in Carroll and Grennan, 1970 must all be reduced by 1.4 cm-1 Mathews, 1971 owing to an error resulting from the incorrect application of the vacuum correction.
8Predissociation above v=1, due to a curve crossing with the a 4Sigma- state at an internuclear distance smaller than re: see Mathews, 1971, Hall and Richards, 1972.
9(B0 and B1 from Porter, Mann, et al., 1965, B2 from Mathews, 1971).
10D1= 7.10E-6 Porter, Mann, et al., 1965, D2= 9.00E-6 Mathews, 1971.
11Radiative lifetime tau(v'=1) = 19.0 ns Hesser and Dressler, 1966, Hesser, 1968, f00(AlarrowX) ~ 0.0027, fel ~ 0.026 Harrington, Modica, et al., 1966, Hesser, 1968. See also Wentink and Isaacson, 1967.
12N'=0 relative to J"=1/2 (average of F"1 and {F"2}).
13Preliminary results of theoretical calculations Mathews, 1971, Hall and Richards, 1972.
14Av=77.12 - 0.655v + 0.0057v2.
15weze = - 0.0011
16Lambda-type doubling; see Porter, Mann, et al., 1965.
17ESR sp. (2Pi3/2)u
18Thermochemical value (mass-spectrom.) Hildenbrand, 1975. From the predissociation in A 2Sigma+; D00 leq 5.74 eV.
19Photoionization Walter, Lifshitz, et al., 1969 and electron impact Hildenbrand, 1975 appearance potential measurements; supported by theoretical calculations O'Hare and Wahl, 1971.
20muel(C-F+)= 0.65 D; polarity predicted by the theoretical work of O'Hare and Wahl, 1971 and Hall and Richards, 1972.


Go To: Top, 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.

Mathews, 1971
Mathews, C.W., Private communication cited in Huber and Herzberg, 1979, 1971, 139. [all data]

Margrave and Wieland, 1953
Margrave, J.L.; Wieland, K., Equilibria involving the CF(g) and CF2(g) radicals at high temperatures, J. Chem. Phys., 1953, 21, 1552. [all data]

Mann, Broida, et al., 1954
Mann, D.E.; Broida, H.P.; Squires, B.E., The decomposition of CF4 flames, J. Chem. Phys., 1954, 22, 348. [all data]

Kuzyakov and Tatevskii, 1958
Kuzyakov, Yu.Ya.; Tatevskii, V.M., New bands of the CF molecule, Opt. Spektrosk., 1958, 5, 699. [all data]

Thrush and Zwolenik, 1963
Thrush, B.A.; Zwolenik, J.J., Predissociation in the absorption spectra of CF and CF2, Trans. Faraday Soc., 1963, 59, 582, https://doi.org/10.1039/tf9635900582 . [all data]

Porter, Mann, et al., 1965
Porter, T.L.; Mann, D.E.; Acquista, N., Emission spectrum of CF, J. Mol. Spectrosc., 1965, 16, 228. [all data]

Carrington and Howard, 1970
Carrington, A.; Howard, B.J., Gas-phase electron resonance spectrum and dipole moment of CF, Mol. Phys., 1970, 18, 225. [all data]

Hesser and Dressler, 1966
Hesser, J.E.; Dressler, K., Radiative lifetimes of ultraviolet molecular transitions, J. Chem. Phys., 1966, 45, 3149. [all data]

Hesser, 1968
Hesser, J.E., Absolute Transition Probabilities in Ultraviolet Molecular Spectra, J. Chem. Phys., 1968, 48, 6, 2518, https://doi.org/10.1063/1.1669477 . [all data]

Wentink and Isaacson, 1967
Wentink, T., Jr.; Isaacson, L., Oscillator strengths of CF and comments on heats of formation of CF and CF2, J. Chem. Phys., 1967, 46, 603. [all data]

Carroll and Grennan, 1970
Carroll, P.K.; Grennan, T.P., The B-X system of CF, J. Phys. B:, 1970, 3, 865. [all data]

Hall and Richards, 1972
Hall, J.A.; Richards, W.G., A theoretical study of the spectroscopic states of the CF molecule, Mol. Phys., 1972, 23, 331. [all data]

Harrington, Modica, et al., 1966
Harrington, J.A.; Modica, A.P.; Libby, D.R., Erratum: Shock-tube determination of the C2(A3«PI» --> X3«PI») and CF(A2«SIGMA»+ --> X2«PI») band-system oscillator strengths, J. Chem. Phys., 1966, 45, 2720. [all data]

Hildenbrand, 1975
Hildenbrand, D.L., Dissociation energy and ionization potential of the molecule CF, Chem. Phys. Lett., 1975, 32, 523. [all data]

Walter, Lifshitz, et al., 1969
Walter, T.A.; Lifshitz, C.; Chupka, W.A.; Berkowitz, J., Mass-spectrometric study of the photoionization of C2F4 and CF4, J. Chem. Phys., 1969, 51, 3531. [all data]

O'Hare and Wahl, 1971
O'Hare, P.A.G.; Wahl, A.C., Molecular orbital investigation of CF and SiF and their positive and negative ions, J. Chem. Phys., 1971, 55, 666. [all data]

Huber and Herzberg, 1979
Huber, K.P.; Herzberg, G., Molecular Spectra and Molecular Structure. IV. Constants of Diatomic Molecules, Van Nostrand Reinhold Company, New York, 1979, 716. [all data]


Go To: Top, Constants of diatomic molecules, References