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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 November, 1975

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 27Al2
A 3Sigmau- 17269.36 278.8 1 H 0.831 -0.0104 0.1907 0.0013  3.9E-7  2.560 A rarrow X R 17234.05 H
missing citation; missing citation
X 3Sigmag- 0 350.01 1 H 2.022 -0.0105 0.2054 0.0012  3.07E-7  2.466  


1From Zeeman, 1954 who wrongly attributed the spectrum to AlC.
2Thermochemical value (mass spectrom.) Stearns and Kohl, 1973. Values in Blue and Gingerich, 1968, Uy and Drowart, 1971 are somewhat higher.


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.

Zeeman, 1954
Zeeman, P.B., Spectrum of the AlC molecule, Can. J. Phys., 1954, 32, 9. [all data]

Stearns and Kohl, 1973
Stearns, C.A.; Kohl, F.J., Mass spectrometric determination of the dissociation energies of gaseous Al2, AlSi, and AlSiO, High Temp. Sci., 1973, 5, 113. [all data]

Blue and Gingerich, 1968
Blue; Gingerich, 16th Annual Conference on Mass Spectrometry and Allied Topics - Paper 129, Pittsburgh, 1968, 0. [all data]

Uy and Drowart, 1971
Uy, O.M.; Drowart, J., Determination by the mass spectrometric Knudsen cell method of the atomization energies of the gaseous aluminium chalcogenides, Al2, AlCu, AlCuS, and AlCuS2, Trans. Faraday Soc., 1971, 67, 1293. [all data]


Go To: Top, Constants of diatomic molecules, References