The fit combines pure rotational as well as rovibrational data of three isotopic species. The OH^– rotational data were taken from
(1) F. Matsushima, T. Yonezu, T. Okabe, K. Tomaru, and Y. Moriwaki, 2006, J. Mol. Spectrosc., 235, 261; and
(2) D. J. Liu, W. C. Ho, and T. Oka, 1987, J. Chem. Phys., 87, 2442.
The OD^– rotational data were published by
(3) G. Cazzoli and C. Puzzarini, 2005, J. Chem. Phys., 123, Art.-No. 041101; and
(4) G. Cazzoli and C. Puzzarini, 2006, Astrophys. J., 648, L79.
Rovibrational transitions for OH^– and ¹⁸OH^– were taken from
(5) J. C. Owrutski, N. H. Rosenbaum, L. M. Tack, and R. J. Saykally, 1985, J. Chem. Phys., 83, 5338;
those of OD^– from
(6) B. D. Rehfuss, M. W. Crofton, and T. Oka, 1986, J. Chem. Phys., 85, 1785.
Predictions with J > 10 should be viewed with some caution; lower-J predictions may be fairly reliable if and only if ion drift effects had negligible effects on the infrared data.
The dipole moment was assumed to agree with that of the main isotopic species, see e017502.cat.