With respect to the Feb. 2005 entry, new and accurate data have been published by
(1) L. Dore, L. Bizzocchi, C. Degle Esposti, and F. Tinti, 2009, Astron. Astrophys. 496, 275.
In order to extrapolate more reliably to higher values of J, a value for the sextic distortion parameter H was derived from HCN, see e027501.cat for references. The predictions are assumed to be reliable to at least 2 THz.
The hyperfine splitting due to the ¹⁴N nucleus was derived from the main isotopomer, see e029506.cat. The splitting is probably accurate to better than 5 kHz. A separate hyperfine calculation is provided for J" ≤ 4. Note: The partition function takes into account the¹⁴N splitting !
The dipole moment was assumed to be the same as that of the main isotopomer, see e029506.cat.