The data refer to the lowest energy syn conformer. The experimental frequencies were taken from
(1) M. Sanz-Novo, A. Belloche, J. L. Alonso, L. Kolesniková, R. T. Garrod, S. Mata, H. S. P. Müller, K. M. Menten, and Y. Gong, 2020, Astron. Astrophys. 639, Art. No. A135.
The parameters differ somewhat from those in (1).
The calculation should be sufficiently accurate for all astronomical observations. Caution is advised for transitions with calculated uncertainties exceeding 0.2 MHz. ¹⁴N hyperfine splitting was deemed to be negligible.
The total dipole moment is from a quantum-chemical study, the ratio is experimental. Both were taken from
(2) A. Maris, 2004, Phys. Chem. Chem. Phys. 6, 2611.