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MD simulations have been performed for NaCl, NaI, and fictitious solutions of discharged counterparts of Na + and Clions to investigate an effect of the charge density of a solute on its solvation in methanol-water mixtures. Solvent-solvent interactions have been described in terms of flexible models, whereas solutes have been considered as charged or uncharged Lennard-Jones spheres. An analysis of solvation shells has been based on radial distribution functions, angular distributions, coordination numbers, and residence times of solvent molecules. Preferential solvation of anions by methanol molecules becomes less pronounced with decreasing charge density of a solute and vanishes for the discharged chloride ion. In contrast to preferential hydration of Na + in water deficit solvents, its uncharged counterpart Na 0 is preferentially solvated by methanol molecules over the whole range of solvent composition. Results for NaCl solution have been compared with those obtained with ab initio ion-solvent potentials and the same model of solvent molecules. The type of ion-solvent potential has small effect on the structure and composition of ionic shells, but its influence on the persistence of the coordination shells is more noticeable.

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Deterministic diffusion-kinetic modeling has been performed to calculate the temperature dependence of the radiation chemical yields (G-values) of the radiolysis products of water. The FACSIMILE numerical method has been used to solve a set of coupled differential equations describing the diffusion and reactions of the species for the temperature range 20-300 "C. The low LET spherically symmetrical case of an "average" spur with 62.5 eV deposited in it has been considered. Modeling calculations have been compared for Gaussian, an exponential distribution, and a distribution with a central minimum assumed as the initial spatial distribution of the hydrated electron (eaq-). In all cases spatial distributions of the other radiolytic products started as Gaussian. To fit the experimental data it has been necessary to assume that the reaction eaq-+ eaq--H2