The frequencies 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.
¹⁴N hyperfine splitting may be resolved at low values of J. Therefore, predictions with ¹⁴N hyperfine splitting are available for J" < 12. The quadrupole coupling constant eQq was assumed to be identical with that of HC₅N while the nuclear spin-rotation constant C was scaled with the rotational constants. These assumptions should be reliable enough for most purposes.
NOTE: The partion function does NOT take into account the hyperfine splitting and no vibrational contributions ! The partition function has to be muliplied by g(¹⁴N) = 3 when ¹⁴N hyperfine splitting is considered !
The dipole moment was assumed to be the same as that of the main species, see e075503.cat.