CDMS

The experimental data were taken from
(1) K. Bolton and R. D. Brown, 1974, Austr. J. Phys. 27, 143;
from
(2) L. Nygaard, J. T. Nielsen, J. Kirchheimer, G. Maltesen, N. Rastrup-Andersen, and G. O. Sørensen, 1969, J. Mol. Struct. 3, 491;
and from
(3) G. Wlodarczak, L. Martinache, J. Demaison, B. P. van Eijck, 1988, J. Mol. Spectrosc. 127, 200.
The parameter set is slightly more extensive than that in (3). Two parameters were estimated from furan. ¹⁴N hyperfine structure was deemed to be irrelevant for astronomical observations and were omitted. Two lines from (3) were omitted from the fit.
The predictions may well be sufficient for all needs of astronomers. Predictions with uncertainties larger than 0.5MHz should be viewed with caution.
Spin-statistics matter for the intensities. The nuclear spin-weight ratio is 5:3 for ortho-c-C₄H₄NH : para-c-C₄H₄NH. The ortho states are described by K_a even, the para states by K_a odd.
The dipole moment was taken from (2).