The two rotational transitions were reported by
(1) M. E. Sanz, M. C. McCarthy, and P. Thaddeus, 2002, Astrophys. J. 577, L71.
Some spectroscopic parameters were kept fixed to values estimated from
(2) S. Thorwirth and M. E. Harding, 2009, J. Chem. Phys. 130, Art. No. 214303.
Transitions obeying b-type selection rules are possible, but very weak and very uncertain. Hence, they do not occur in the predictions. Predictions with hyperfine splitting are also available up to J" = 4 with related partition function values. Predictions with uncertainties exceeding 200 kHz should be viewed with caution. This should not be a severe restriction for astronomical observations.
The ab initio dipole moment was taken from (2).