The experimental frequencies have been taken almost entirely from
(1) I. Haykal, R. A. Motyenko, L. Margulès, and T. R. Huet, 2013, Astron. Astrophys. 549, Art. No. A96.
Initial data from
(2) K.-M. Marstokk and K. Møllendal, 1973, J. Mol. Struct. 16, 259
were omitted because of the large uncertainties of all lines and because of large deviation of some lines.
Additional data from
(3) P. B. Carroll, B. A. McGuire, D. P. Zaleski, J. L. Neill, B. H. Pate, S. L. Widicus Weaver, 2013, J. Mol. Spectrosc. 284-285, 18,
however, were included, except for two transition frequencies with residuals larger than three times the experimental uncertainties, even though the contribution to the fit is negligible.
Intensity cut-offs were lowered compared to the main isotopolog in order to merge all transition frequencies. The predictions are deemed to be accurate and reliable throughout.
Estimated factors for the vibrational contributions to the partition function will be provided.
The dipole moment was assumed to agree with that of the main species, see c060501.cat.