The experimental frequencies have been reported by
(1) S. G. Kukolich and A. C. Nelson, 1971, Chem. Phys. Lett. 11, 383;
by
(2) E. Hirota, R. Sugisaki, C. J. Nielsen, and G. O. Sørensen, 1974, J. Mol. Spectrosc. 49, 251;
by
(3) F. F. Gardner, P. D. Godfrey, and D. R. Williams, 1980, Mon. Not. R. Astr. Soc. 193, 713;
by
(4) E. M. Moskienko and S. F. Dyubko, 1991, Radiophys. Quant. Electr. 34, 181;
by
(5) E. M. Vorob'eva and S. F. Dyubko, 1994, Radiophys. Quant. Electr. 37, 155;
by
(6) S. Blanco, J. C. Lopez, A. Lessari, and J. L. Alonso, 2006, J. Am. Chem. Soc. 128, 12111;
and by
(7) A. V. Kryvda, V. G. Gerasimov, S. F. Dyubko, E. A. Alekseev, R. A. Motiyenko, 2009, J. Mol. Spectrosc. 254, 28.
With respect to the May 2009 entrty, additional submillimeter data up to 930 GHz were taken from
(8) R. A. Motiyenko, B. Tercero, J. Cernicharo, and L. Margulès, 2012, Astron. Astrophys. 548, Art. No. A71.
Please note: the data used in (2) were taken from
(9) C. J. Nielsen, 1973, PhD thesis, Københavns Universitet, Denmark.
Claus Nielsen and Matt Johnson are thanked for providing the data from (9).
All data were used with ¹⁴N hyperfine splitting as far as it had been resolved. The spectroscopic parameters agree largely with the S-reduction set in (8). Predictions with uncertainties larger than 1 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' ≤ 20 and frequencies below 200 GHz along with partition function values.
Vibrational contributions to the partition function will be provided.
The dipole moment was reported in
(10) R. J. Kurland and E. B. Wilson, 1957, J. Chem. Phys. 27, 585.