N-Methaniminyl, Methyleneamidogen, X 2B2
Species tag 028502
Date of EntryJuly 2000
ContributorH. S. P. Müller

The experimental lines are from (1) S. Yamamoto and S. Saito, 1992, J. Chem. Phys. 96, 4157.
The parameters used in the present fit differ slightly from those in (1). The fourth quantum number is an aggregate spin number; see general section. Translation to the more commonly used quantum numbers is possible with the h2cn.out file. Note: Here the spin angular momentum I due to the two equivalent H nuclei is the last one coupled to the rotational angular momentum because of restrictions in the fitting program. In contrast, in (1) I(N) is the spin angular momentum coupled to the rotational angular momentum last as would be expected from the magnitudes of the hyperfine structure effects.
The dipole moment is from an ab initio calculation by
(2) D. C. Cowles, M. J. Travers, J. L. Frueh, and G. B. Ellison, 1991, J. Chem. Phys. 95, 4702. At low temperatures, it may be necessary to discern between ortho-H2CN and para-H2CN. The ortho states are described by Ka even, the para states by Ka odd. There are three times as many levels for ortho-H2CN than there are for para-H2CN. Thus, for transitions with unresolved 1H hyperfine splitting the nuclear spin-weight ratio is 3 : 1 between ortho-H2CN and para-H2CN. However, for transitions with resolved 1H hyperfine splitting no non-trivial spin-statistics have to be considered. The NKaKc = 111; n, F + 1/2 = 13, 1 (or J, F1 = 0.5, 0.5) is the lowest para state. It is 10.6256 cm–1 above ground.

Lines Listed6519
Frequency / GHz< 2000
Max. J28
log STR0-7.5
log STR1-5.0
Isotope Corr.-0.0
Egy / cm-10.0
 µa / D2.54
 µb / D 
 µc / D 
 A / MHz284343.
 B / MHz39158.3
 C / MHz34245.5
detected in ISM/CSMyes

Database maintained by Holger S. P. Müller and Sven Thorwirth, programming by D. Roth and F. Schloeder