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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 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 12CD
G 1           G larrow X 72955
missing citation
F 2Sigma+ [65605]    [6.86] 2     [1.194] F larrow X R 64563.9 3 Z
missing citation
D 2Pii 59038 4 (2025)   [7.425]   [0.00040]  [1.1474] D larrow B V 33212.0 3 Z
missing citation
C 2Sigma+ [31818.1] 5 2081.3 Z 66.79 6 5.364 7.879 5 7 0.283 8  [0.00045] 9  [1.1138] C lrarrow X 7 10 VR 31801.3 3 Z
Gero, 1941; Herzberg and Johns, 1969
B 2Sigma- 26043 1652.5 11 Z 123.8  7.104 7 0.341 -0.095 [0.000636] 12  1.1730 B lrarrow X 7 10 R 25796.9 3 Z
Shidel, 1936; Gero, 1941; Herzberg and Johns, 1969
A 2Delta 23184.4 2203.3 Z 78.50  8.032 8 9 0.260  [0.00045] 13  1.1032 A lrarrow X 10 V 23225.1 3 Z
Gero, 1941
X 2Pir 0 14 2099.75 Z 34.02  7.806 15 0.208  [0.00042] 16  [1.1190]  


13d complex consisting of 2Sigma, 2Pi, 2Delta.
2Heterogeneous predissociation.
3The band origins refer to the zero points of the Hill-Van Vleck formulae for the ground and excited (Lambda neq 0) states. See also missing citation.
4A= -27.7.
5Spin-splitting constant gamma0= +0.06 Herzberg and Johns, 1969.
6omegaeze = -1.15; these two constants are derived under the assumption that DeltaG of X 2Pi is linear in v+1/2.
7Lifetime and predissociation see Hesser and Lutz, 1968, Herzberg and Johns, 1969, Hesser and Lutz, 1970. For B 2Sigma-, v=0, breaking off occurs above N'=24, for v=1 above N'=16. For C 2Sigma+ the predissociation is much weaker for CD than for CH; see note n of CH.
8alphav= +0.0075(v+1/2)2 - 0.005(v+1/2)3.
9D1(E-4 cm-1)= 4.9, D2(E-4 cm-1)= 5.2, D3(E-4 cm-1)= 6.3, D4(E-4 cm-1)= 9.
10Franck-Condon factors Halmann and Laulicht, 1966, Liszt and Smith, 1972.
11The B state is too shallow for these constants to have much physical meaning.
12D1 = 7.2E-4, D2 = 13.9E-4.
13D1 = 4.7E-4.
14A = +27.95.
15Lambda-type doubling, Deltanu ~ 0.009N(N+1) for higher N values. The splitting for J= 1/2 is predicted Hammersley and Richards, 1974 to be 1241 MHz.
16missing note
17From the predissociation in B 2Sigma- of CD. The revised value of D00(CH) would imply D00C(CD) = 3.512 eV.
18From I.P. (CH).


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.

Gero, 1941
Gero, L., Das bandenspektrum des CD-molekuls, Z. Phys., 1941, 117, 709. [all data]

Herzberg and Johns, 1969
Herzberg, G.; Johns, J.W.C., New spectra of the CH molecule, Astrophys. J., 1969, 158, 399. [all data]

Shidel, 1936
Shidel, T., 4. The band spectra of carbon deuteride, Jpn. J. Phys., 1936, 11, 23. [all data]

Hesser and Lutz, 1968
Hesser, J.E.; Lutz, B.L., Direct measurements of predissociation probabilities in CH and CD molecules, Phys. Rev. Lett., 1968, 20, 363. [all data]

Hesser and Lutz, 1970
Hesser, J.E.; Lutz, B.L., Probabilities for radiation and predissociation. II. The excited states of CH, CD, and CH+, and some astrophysical implications, Astrophys. J., 1970, 159, 703. [all data]

Halmann and Laulicht, 1966
Halmann, M.; Laulicht, I., Isotope effects on vibrational transition probabilities. IV. Electronic transitions of isotopic C2, CO, CN, H2, and CH molecules, Astrophys. J. Suppl. Ser., 1966, 12, 307. [all data]

Liszt and Smith, 1972
Liszt, H.S.; Smith, W.H., RKR Franck-Condon factors for blue and ultraviolet transitions of some molecules of astrophysical interest and some comments on the interstellar abundance of CH, CH+, and SiH, J. Quant. Spectrosc. Radiat. Transfer, 1972, 12, 947. [all data]

Hammersley and Richards, 1974
Hammersley, R.E.; Richards, W.G., «LAMBDA»-type doubling in the CD molecule, Astrophys. J., 1974, 194, 61. [all data]


Go To: Top, Constants of diatomic molecules, References