Geminate ion recombination of electron and radical cation in non-polar liquid studied by laser-synchronized pico and subpicosecond pulse radiolysis

The geminate ion recombination of the electron and the radical cation is one of the most important phenomena in the primary process of radiation chemistry. The behavior of the electron in the nonpolar liquid has been studied experimentally and theoretically. However, it was difficult to investigate the time-dependent behavior, because of the fast recombination process. A new picosecond pulse radiolysis system for the absorption spectroscopy to observe ultra fast phenomena was developed. The system was composed of a 38 MeV picosecond and subpicosecond electron L-band linac for the irradiation source and a femtosecond laser system for the analyzing light. The laser pulse was synchronized with the electron pulse by using the common radio frequency. The time-dependent behavior obtained in the pulse radiolysis was analyzed by the diffusion theory and discussed from the view point of the initial spatial distribution of the geminate pair and the reaction mechanism of the recombination process