The experimental measurements were taken from
(1) G. Klapper, L. Surin, F. Lewen, H. S. P. Müller, I. Pak, G. Winnewisser, 2003, Astrophys. J., 582, 262.
While the current predictions are expected to be sufficient for most astronomical purposes, improved data will be presented once an isotopic invariant fit has been performed. That dataset shall take into account data from
(2) G. Cazzoli, L. Dore, C. Puzzarini, S. Beninati, 2002, Phys. Chem. Chem. Phys., 4, 3575.
The dipole moment and dipole centrifugal corrections are taken from
(3) D. Goorvitch, 1994, Astrophys. J. Suppl. 95, 535.