Nature of the physicochemical process in water photolysis uncovered by a computer simulation

Kai, Takeshi   ; Toigawa, Tomohiro   ; Ukai, Masatoshi*; Fujii, Kentaro*; Watanabe, Ritsuko*; Yokoya, Akinari*

New insight into water radiolysis and photolysis is indispensable in the dramatic progress of sciences and technologies in various research areas. In the radiation field, reactive hydrated electrons are considerably produced along radiation tracks. Although the formation results from a transient dynamic correlation between ejected electrons and water, the individual mechanisms of electron thermalization, delocalization, and polarization are unknown. Using a dynamic Monte Carlo code, we show herein that the ejected electrons are immediately delocalized by molecular excitations in parallel with phonon polarization and gradually thermalized by momentum transfer with an orientation polarization in a simultaneous manner. Our results show that these mechanisms heavily depend on the intermolecular vibration and rotation modes peculiar to water. We expect our approach to be a powerful technique for connecting physical and chemical processes in various solvents.