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Transition frequencies were taken from astronomical
observations by
(1) R. Fuentetaja, C. Cabezas, M. Agúndez, B. Tercero,
N. Marcelino, J. R. Pardo, P. de Vicente, and J. Cernicharo,
2022, Astron. Astrophys. 663, Art. No. L3.
This work also reports unpublished laboratory data from
(2) M. C. McCarthy,
2022, unpublished.
Initial estimates of the quartic distortion parameters and
of the dipole moments components were taken from a B3LYP
quantum-chemical calculation by
(3) H. S. P. Müller, 2022, unpublished;
the final parameter set differs somewhat from those in (1) and (2).
The b-dipole moment component is very much weaker than
the a-component, and its magnitude should be viewed with
some caution. Therefore, no b-type transitions were
calculated even if some were observed in the laboratory.
The data set is somewhat limited. The calculations were therefore
truncated at 120 GHz (J = 66) and
Ka = 5.
The calculations should be sufficient for searches in cold and
possibly even luke warm environments. Transition frequencies
with J larger than 45 should be viewed with caution.
The 14N hyperfine splitting can be resolved
for low values of J. Therefore, a separate
hyperfine calculation is provided up to J = 15.
The partition function takes into account the spin-multiplicity
of the 14N nucleus.
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