Transition frequencies were taken from
(1) L. Bonah, J.-C. Guillemin, A. Belloche, S. Thorwirth, H. S. P. Müller, and S. Schlemmer, 2025, ACS Earth Space Chem. 9, 864.
A small number of microwave transitions came from
(2) R. A. Creswell, P. J. Manor, R. A. Assink, and R. H. Schwendeman, 1977, J. Mol. Spectrosc. 64, 365.
The entry is based on the supplementary files of (1). The calculated transition frequencies are deemed to be accurate enough. Frequencies with uncertainties larger than 0.1 MHz should be viewed with caution.
The partition function values below refer to the ground vibrational state only. Vibrational correction factors can be derived for the main isotopolog in the harmonic approximation.
The ground state dipole moment components were determined in (2); the c-component was taken from (1).