The microwave spectra of cyanamide: Conclusions from [formula omitted]a transitions

Abstract

Microwave spectra have been observed for the species NH 2CN, NHDCN, ND 2CN, 15NH 2CN, NH 2C 15N, 15ND 2CN and ND 2C 15N. The nonplanar nature of the molecule is confirmed and the following structural parameters obtained N 1N 2 = 2.506 ± 0.002 Å, N 1C = 1.346 ± 0.005 Å, CN 2 = 1.160 ± 0.005 Å, N 1H = 1.001 ± 0.015 Å, HN̂ 1H = 113°31′ ± 2°, out of plane angle (see text) = 37°58′ ± 1°. (N 1 is the amino nitrogen atom and N 2 that the cyanide group.) From an analysis of perturbations occurring in the spectra the lowest inversion splittings in NH 2CN, NHDCN and ND 2CN have been estimated as 50, 33 and 15 cm −1, respectively. Calculations concerning the barrier to inversion are presented assuming a Manning type potential function. The μ a component of the dipole moment is measured as 4.32 ± 0.08 D for the vibrational ground state, and 4.27 ± 0.08 D for the first excited inversion state.