Time-dependent yield of OH radicals in the low linear energy transfer radiolysis of water between 25 and 350 °C

Monte Carlo simulations were used to calculate time-dependent yields of OH radicals in the low-LET radiolysis of water from 25 to 350 °C. The excellent agreement found, at 25 °C, with both OH yields directly measured in picosecond pulse radiolysis and those inferred from scavenger experiments, resolves a long-standing problem in models of the radiation chemistry of water concerning short-time OH decay kinetics. Above ∼200 °C, the OH yields markedly increased at long times due to the reaction H + H2O → H2 + OH. Our results suggest a way to assess this reaction’s rate constant, which is still controversial.