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 μm. 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 ν4out-of-plane bending mode. All assigned transitions obeya-dipole selection rules. The data were combined with previously reported microwave results (Y. Endo, C. Yamada, S. Saito, and E. Hirota,J. Chem. Phys.79, 1605 (1983)) and subjected to a least-squares fit to determine the parameters of the effective Hamiltonian describing thev4= 0 and 1 vibrational levels of the CH2F radical.