Knowledge Bank

The hyperfine $\Lambda$-doubling transitions originating in the lower rotational states of the free radicals OH, OD, SH, and SD were observed using the molecular beam electric resonance technique. The observed transitions are in the frequency range from 16 to 8500 MHz. The experimental spectra were used in a least squares fit to the calculated spectra from which fine and hyperfine coupling constants and the electric dipole moments for all the molecules were obtained. The radicals were produced in a reaction type source and a discussion on the production method will be given.