Monte Carlo simulations were used to calculate time-dependent yields of (OH)-O-center dot radicals in the low-LET radiolysis of water from 25 to 350 degrees C. The excellent agreement found, at 25 degrees C, with both (OH)-O-center dot 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)-O-center dot decay kinetics. Above similar to 200 degrees C, the (OH)-O-center dot yields markedly increased at long times due to the reaction H-center dot + H2O -> H-2 + (OH)-O-center dot. Our results suggest a way to assess this reaction's rate constant, which is still controversial. (C) 2013 Elsevier B. V. All rights reserved.