The far-infrared laser magnetic resonance spectrum of CH2F

Far-infrared laser magnetic resonance (FIR-LMR) spectra due to the CH2F radical have been recorded on seven laser Lines at wavelengths between 301 and 568 mu m. Observed resonances were assigned to fine and hyperfine components of pure rotational transitions of CH2F in the ground vibrational state and the first excited state of the nu(4) out-of-plane bending mode. All assigned transitions obey a-dipole selection rules. The data were combined with previously reported microwave results (Y. Endo, C. Yamada, S. Saito, and E. Hirota, J. Chern. Phys. 79, 1605 (1983)) and subjected to a least-squares fit to determine the parameters of the effective Hamiltonian describing the nu(4) = 0 and 1 vibrational levels of the CH2F radical. (C) 1999 Academic Press.