The molecule exists in two conformers, the second one being about 1.7 kcal/mol (~840 K) higher in energy. This entry considers only the low energy trans conformer. The transition frequencies were summarized by
(1) L. Kolesniková, T. Uhlíková, Jan Koucký, K. Luková, D. Habiger, P. Kania, J.-C. Guillemin, and Š. Urban, 2023, Astrophys. J., 944, Art. No. 10.
The line list contains microwave data from
(2) E. Bjarnov, 1979, Z. Naturforsch. A, 34, 1269.
The calculation should be sufficiently accurate for observational purposes; caution is advised for transition frequencies with calculated uncertainties exceeding 0.2 MHz.
The a-dipole moment component was taken from
(3) R. D. Brown, P. D. Godfrey, and M. Woodruff, 1979, Aust. J. Chem., 32, 2103;
the b-component is an average of values from (2) and (3).