Frequencies without hyperfine splitting have been reported in
(1) A. J. Alexander, H. W. Kroto, and D. R. M. Walton, 1976, J. Mol. Spectrosc. 62, 175 and in
(2) L. Bizzocchi, C. Degli Esposti, and P. Botschwina, 2004, J. Mol. Spectrosc. 225, 145.
Transitions involving ¹⁴N hyperfine splitting were reported in
(3) M. E. Sanz, M. C. McCarthy, and P. Thaddeus, 2005, J. Chem. Phys. 122, Art. No. 194319.
The partion function does not take into account vibrational contributions !
The dipole moment was assumed to be the same as that of the main species, see e075503.cat.