The experimental frequencies have been reported by
(1) F. F. Gardner, P. D. Godfrey, and D. R. Williams, 1980, Mon. Not. R. Astr. Soc. 193, 713;
by
(2) S. Blanco, J. C. Lopez, A. Lessari, and J. L. Alonso, 2006, J. Am. Chem. Soc. 128, 12111;
and by
(3) A. V. Kryvda, V. G. Gerasimov, S. F. Dyubko, E. A. Alekseev, R. A. Motiyenko, 2009, J. Mol. Spectrosc. 254, 28.
Additional microwave transitions were also considered. These were taken from
(4) M. Stubgaard, PhD thesis, 1978, Københavns Universitet.
Claus Nielsen and Matt Johnson are thanked for providing the data from (4).
With respect to the May 2009 entrty, additional submillimeter data up to 930 GHz were taken from
(5) R. A. Motiyenko, B. Tercero, J. Cernicharo, and L. Margulès, 2012, Astron. Astrophys. 548, Art. No. A71.
Diagonal sextic and higher distortion parameters were taken from the main isotopolog, the off-diaginal ones were scaled.
Predictions with uncertainties larger than 0.3 MHz should be viewed with caution. This is probably not a limitation for any astronomical observations.
¹⁴N hyperfine splitting may be resolved for low values of J. Therefore, a separate hyperfine calculation is provided for J" = J' ≤ 10 and frequencies below 100 GHz along with partition function values.
Vibrational contributions to the partition function will be provided in the future.
The dipole moment was assumed to agree with that of the main isotopolog, which was determined by
(6) R. J. Kurland and E. B. Wilson, 1957, J. Chem. Phys. 27, 585.