DOUBLE-RESONANCE SPECTRA OF (CH3OH)-O-18

Two double-resonance techniques have been used to confirm previously proposed assignments of infrared transitions in the CH3OH-O-18 molecule. The techniques involve a cw CO2 laser, and they complement each other. The infrared-infrared double-resonance technique is used for probing accidental coincidences between the CO2 laser lines and Stark-tuned levels of E symmetry. Two such coincidences have been assigned, and the permanent electric dipole moment components mu-a" and mu-a' have been determined, for the first time to our knowledge, in this molecule for the ground state and the CO stretch state, respectively. The infrared radio-frequency double-resonance technique has been used to probe a level of A symmetry. This observation has permitted a more accurate determination of molecular asymmetry parameters with (n, K) = (0, 3) in both vibrational levels.