First Observation of Picosecond Kinetics of Hydrated Electrons in Supercritical Water

For the first time, a setup is performed to carry out picosecond time-resolved experiments in supercritical water (SCW) by pulse radiolysis. The kinetics of the decay of the hydrated electron is measured by transient absorption in the near IR on a time-scale ranging from 50 ps to 6 ns. The decay of the hydrated electrons in supercritical conditions shows a fast component at a short time below 500 ps, which is assigned to the reaction of the hydrated electron with the hydronium cation formed by radiolysis. The dependence of the kinetics on the density of SCW is also examined.