Electronic spectra of the jet-cooled 1-methylvinylthio radical

Electronic spectra of the $\tilde B - \tilde X$ B ̃ − X ̃ transition of the 1-methylvinylthio radical were observed in a discharged jet of propylene sulfide by laser-induced fluorescence spectroscopy. Identification of the spectral carrier was made by comparing the observed spectra with results of molecular orbital calculations, in particular, for vibrational frequencies, rotational contour simulations, and the Franck-Condon simulations. Vibrational structures observed in the electronic spectra indicate that the 1-methylvinylthio radical can be regarded as a molecule with C s symmetry at the zero-point levels of both the excited and ground states.