New v = 1 – 0 infrared data with megahertz were included in the initial fit to improve the first entry from Apr. 2003. Details of the new fit as well as the data are presented in
(1) C. R. Markus, J. M. Hodges, A. J. Perry, G. S. Kocheril, H. S. P. Müller, and B. J. McCall, 2016, Astrophys. J. 817, Art. No. 138.
The N = 1 – 0 rotational transition frequencies with HFS splitting were taken from
(2) J. P. Bekooy, P. Verhoeve, W. L. Meerts, and A. Dymanus, 1985, J. Chem. Phys. 82, 3868.
The N = 13 – 12 transition frequencies with FS splitting were reported in
(3) D.-L. Liu, W.-C. Ho, and T. Oka, 1987, J. Chem. Phys. 87, 2442.
Vibration-rotation transitions up to v = 5 – 4 were also included in the fit. These were published in
(4) B. D. Rehfuss, M.-F. Jagod, L.-W. Xu, and T. Oka, 1992, J. Mol. Spectrosc. 151, 59.
The predictions had been accurate enough for moderate resolution spectrometers (e.g. PACS@Herschel). They may now be accurate enough for high resolution spectrometers (e.g. GREAT@SOFIA).
The electric dipole moment is from an ab initio calculation by
(5) H.-J. Werner, P. Rosmus, and E.-A. Reinsch, 1983, J. Chem. Phys. 79, 905.