Development of a Femtosecond Pulse Radiolysis for Reaction Analysis in Nano-space

Pulse radiolysis based on linear accelerator is studied in Osaka University for the observation of radiation-induced ultrafast physical and chemical reactions. A subpicosecond pulse radiolysis was developed by using a subpicosecond electron pulse from L-band linear accelerator and a femtosecond laser pulse. The geminate ion recombination in n-dodecane was investigated by using the subpicosecond pulse radiolysis. The geminate decay of cation radical after 50 ps can be explained by the diffusion theory. However, the difference between the experimental result and the theory was observed within 50 ps. In order to explain the difference, a new femtosecond pulse radiolysis based on a photocathode RF gun linac is developed. A time resolution of <100 fs is expected in the pulse radiolysis system for the analysis of ultrafast physical and chemical reactions in nano-space.