RESONANCE-ENHANCED MULTIPHOTON IONIZATION SPECTROSCOPY OF DIMETHYL SULFIDE

We report the first multiphoton study of the electronic spectrum of th e dimethyl sulfide molecule. The interpretation we present is based on analysis of the two- and three-photon resonance enhanced multiphoton ionisation (REMPI) spectra and measurements of the kinetic energies of the photoelectrons resulting from the REMPI process. Members of four (possibly five) Rydberg series are identified and a refined value of t he first ionisation limit of dimethyl sulfide is obtained: E(i) = 8.71 0+/-0.005 eV (70250+/-40 cm(-1)). As in our previous study of the rela ted divalent sulfide methanethiol, we detect the presence of slower el ectrons in the photoelectron spectra which can be interpreted in terms of near resonant inter-Rydberg state vibronic mixing.