The lines have been reported in
(1) T. Amano and T. Amano, 1991, J. Chem. Phys. 95, 2275, and in
(2) M. C. McCarthy, A. L. Cooksy, S. Mohamed, V. D. Gordon, and P. Thaddeus, 2003, Astrophys. J. Suppl. Ser. 144, 287.
With respect to th March 2003 entry, additional submillimeter transitions were used in the fit. These were reported in
(3) A. Maeda, H. Habara, and T. Amano, 2007, Mol. Phys. 105, 477.
The fit has been carried out using constants and quantum numbers of Hund's case (b). ¹⁴N hyperfine splitting was not resolved for N" ≥ 10. Therefore, the new default entry does not consider this splitting ! However, it has to be considered in the microwave and lower millimeter wave regions. Therefore, a separate calculation with ¹⁴N hyperfine splitting is provided up to 141 GHz. The partition function takes into account the spin multiplicity g_I = 3 of the ¹⁴N nucleus !
The dipole moment is from an ab initio calculation by
(4) H. S. P. Müller, unpublished.