FAR INFRARED-LASER MAGNETIC-RESONANCE DETECTION OF CHD ((X)OVER-TILDE(3)A'')

Far infrared laser magnetic resonance (FIR-LMR) spectra of the CHD rad ical in its (X) over tilde(3)A'' electronic ground state were observed and assigned. The radicals were generated in the reaction of Na atoms with CHDBr2. LMR spectra were observed using seven laser lines at wav elengths around 100 to 200 mu m. The spectra were assigned to six diff erent rotational transitions and the molecular parameters of CHD were determined by a least squares fit. A number of additional transitions, observed using a laser line at lambda=184.3 mu m but not yet assigned in detail, were attributed to a coupling between the accidentally alm ost degenerate N-KaKc=5(05) and 4(13) rotational levels induced by the epsilon(ab) term in the spin-rotation Hamiltonian and by the off-diag onal components of the hyperfine coupling tenser.