The measurements of the lower spin component were taken from
(1) M. C. McCarthy, A. L. Cooksy, S. Mohamed, V. D. Gordon, and P. Thaddeus, 2003, Astrophys. J. Suppl. Ser. 144, 287.
The unresolved HFS doublets were treated with 2 kHz uncertainties instead of the reported 5. The calculation should be viewed with caution above 58 GHz. In addition, the hyperfine structure splitting should be viewed with some caution below 7 GHz.
The partition function takes into account the higher spin component as far as possible at present. It is essentially converged at 225 K. The slight incompleteness at higher T has negligible effect on the calculated intensities.
The dipole moment is from a quantum chemical calculation in (1).