The data have been published in
(1) Y. Kabbadj, M. Herman, G. DiLonardo, L. Fusina, and J. W. C. Johns, 1991, J. Mol. Spectrosc., 150, 535.
The ν₅ lines were also used in the fit. An electronic line list was kindly provided by M. Herman.
Transitions up to J = 40 should be predicted reliably; i.e. they should be found within 3 – 10 times the predicted uncertainties of the line.
With respect to the Mar. 2006 entry, an experimental transition dipole moment for C₂H₂ was used in the prediction. It was reported by
(2) S. Robert, M. Herman, J. van der Auwera, G. Di Lonardo, L. Fusina, G. Blanquet, M. Lepere, and A. Fayt, 2007, Mol. Phys. 105, 559;
and
M. Herman, 2007, private communication.
Note: The value has a reported uncertainty of about 20 %; the intensities are thus uncertain to about 40 %. At the lower limit, this value agrees reasonably well with the transition dipole moment 0.0358 D of the corresponding C₂D₂ vibration determined by Stark measurements and reported by
(3) W. J. Lafferty, R. D. Suenram, and D. R. Johnson, 1977, J. Mol. Spectrosc. 64, 147.
However, the two values can not expected to be the same !
The version number has been retained, the intensity cut-off and the number of lines have changed slightly.
State numbers 1 and 2 refer to v₅ = 1 and v₄ = 1, respectively. The predictions consider the 3 : 1 intensity ratio of the ortho : para spin modifications. The partition function takes into account v = 0, v₄ = 1, and v₅ = 1. The individual contributions are available.