ARE MODELS OF ANION HYDRATION OVERBOUND ? THE SOLVATION OF THE ELECTRON AND CHLORIDE ANION COMPARED

Abstract
By means of a fully polarizable model for the chloride ion-water interaction we show that the modelling of anion solvation suffers from a similar inconsistency as the current electron-solvent potentials. Either the bulk hydration enthalpies are correct with the first hydration shell overbound, or the potential is adapted to describe the local environment of the solute at the expense of a major loss of solvation enthalpy. It is argued that boundary effects in the simulation are at least partly responsible for this dilemma. A further parallel between a polarizable aqueous halide ion and the solvated electron is the anisotropy in the surrounding solvent, which is reflected in an asymmetry in the electronic excitation spectrum.