Radiolysis of supercritical water at 400 °C and liquid-like densities near 0.5 g/cm 3 — A Monte Carlo calculation

Monte Carlo simulations are used to calculate the primary radical yields [Formula: see text], g( • OH), the sum [[Formula: see text] + g( • OH) + g(H • )], and the ratio g(H • )/[Formula: see text] in the low linear energy transfer (LET) radiolysis of supercritical water (SCW) at 400 °C in the high-density, liquid-like region near ∼0.5 g/cm 3 . Using all the currently available information on the reactivities and diffusion coefficients of the radiation-induced species under these conditions, and assuming the aqueous medium to be a “continuum”, a good accord is found between our calculations and the available experimental data. In particular, our computed [Formula: see text] yields at 60 ps and 1 ns compare very well with recently reported direct time-dependent [Formula: see text] yield measurements in SCW (D 2 O) at 400 °C and 0.570 g/cm 3 using picosecond pulse radiolysis experiments.