The transition frequencies are from astronomical observations by
(1) M. Agúndez, C. Cabezas, N. Marcelino, R. Fuentetaja, B. Tercero, P. de Vicente, and J. Cernicharo, 2022, Astron. Astrophys. 669, Art. No. L1.
Hyperfine parameters were evaluated via a quantum-chemical calculation by
(2) H. S. P. Müller, 2022, unpublished.
The calculations should be sufficient for observations in cold sources. They should be viewed with some caution beyond 90 GHz.
¹⁴N hyperfine splitting can be resolved at low quantum numbers. Therefore, a separate calculation with ¹⁴N hyperfine splitting is provided up to J' = 5.
The hyperfine frequencies should be viewed with some caution throughout. The partition function includes the spin-multiplicity of two N nuclei even if the splitting of the inner N is probably very difficult to resolve.
The dipole moment is from a quantum-chemical calculation in (1).