Microwave rest frequencies were obtained from laboratory measurements by
(1) J. Cernicharo, C. Cabezas, Y. Endo, M. Agúndez, B. Tercero, J. R. Pardo, N. Marcelino, and P. de Vicente, 2021, Astron. Astrophys. 650, Art. No. L14.
Additional higher order parameters were estimated from HC(S)CN, see e071509.cat.
The calculations may be sufficiently accurate for observations of cold sources. Transition frequencies were trancated in frequency, and in K_a to 2. b-type transitions can not be calculated reliably at present and were omitted. Transition frequencies with J ≥ 7 or with K_a = 2 should be viewed with great caution.
The ¹⁴N hyperfine splitting is resolvable at lower frequencies or at lower quantum numbers. Therefore, a separate calculation with hyperfine structure is available with J up to 5.
The dipole moment of the main isotopolog is from a quantum-chemical calculation in (1).