The far-infrared laser magnetic resonance spectrum of CH2F

Far-infrared laser magnetic resonance (FIR-LMR) spectra due to the CH2F rad ical have been recorded on seven laser Lines at wavelengths between 301 and 568 mu m. Observed resonances were assigned to fine and hyperfine componen ts of pure rotational transitions of CH2F in the ground vibrational state a nd the first excited state of the nu(4) out-of-plane bending mode. All assi gned 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 th e nu(4) = 0 and 1 vibrational levels of the CH2F radical. (C) 1999 Academic Press.