Diffusion-kinetic modeling of the electron radiolysis of water at elevated temperatures

Abstract

The temperature dependence of the chemistry in the track of a fast electron in water has been examined with a deterministic diffusion-kinetic model. The model calculations suggest that there is an increase in the yields of the hydrated electron and hydroxyl radical and a decrease in the yields of molecular hydrogen and hydrogen peroxide with increasing temperature. These results are consistent with most of the experimental data. It is found that the best fit to the experimental data occurs when the radius of the initial spatial distribution of the hydrated electron is dependent on a process which scales according to an Arrhenius-like equation with an activation energy similar to that for electron movement between potential traps in water. The radii of the initial spatial distributions of all the other species appear to be independent of the temperature. The predictions of the model suggest that the initial radiation chemical yields of the reactive species are independent of temperature. An additional thermally dependent reaction for the decomposition of water is not required for the model predictions to match the experimental data. 47 refs., 8 figs., 1 tab.