Unraveling complex three-body photodissociation dynamics of dimethyl sulfoxide: a femtosecond time-resolved spectroscopic study.

Photodissociation of dimethyl sulfoxide at 200 nm has been studied using femtosecond time-resolved spectroscopy. The temporal evolutions of the initial state, intermediates, and products (CH3 and SO) were measured by means of fs pump-probe mass-selected multiphoton ionization and laser-induced fluorescence. Femtosecond time-resolved photofragment translational spectroscopy was also employed to measure the CH3 product kinetic energy distributions as a function of reaction time. The ionization experiments revealed that there are at least three major CH3 product components, whereas the fluorescence experiments indicated that two SO product components are present. The combination of experimental and theoretical results suggested a complex multichannel mechanism involving both concerted and stepwise three-body dissociation pathways.