Transition frequencies were taken from
(1) M. C. McCarthy, K. L. K. Lee, P. B. Carroll, J. P. Porterfield, P. B. Changala, J. H. Thorpe, and J. F. Stanton, 2020, J. Phys. Chem. A 124, 5170;
and from observational data from
(2) R. Fuentetaja, C. Cabezas, M. Agúndez, B. Tercero, N. Marcelino, J. R. Pardo, P. de Vicente, and J. Cernicharo, 2022, Astron. Astrophys. 663, Art. No. L3;
After omission of one line from (1) with large resiual, the uncertainties were deemed too conservative and were adjusted from 2 to 1 kHz. Initial estimates of the quartic distortion parameters were taken from a B3LYP quantum-chemical calculation by
(3) H. S. P. Müller, 2022, unpublished;
the final parameter set differs somewhat from those in (1) and (2).
The data set is somewhat limited. The calculations were therefore truncated at 120 GHz and at J = 66. The calculations should be sufficient for searches in cold and luke warm environments. Transition frequencies with calculated uncertainties exceeding 0.1 MHz should be viewed with caution.
The dipole moment is from a quantum-chemical calculation by
(4) K. L. K. Lee and M. C. McCarthy, 2019, J. Phys. Chem. Lett. 10, 2408.
The magnitude of the b-component should be viewed with some caution.