Nonlocal electrostatic theory of ion solvation: A combination of the overscreening effect in the dielectric response of the medium with a smeared ion charge distribution

Factors responsible for the considerable decrease in the solvation energy values calculated by Kornyshev and Sutmann using the ``smeared Born sphere'' model have been examined. The W values for the charge density distribution selected by Kornyshev and Sutmann and for the same distribution but confined within the ion cavity have been compared. This comparison enables the conclusion that charge smearing into the ion cavity leads only to an increase in solvation energy, and the predicted values can only be decreased down to the experimental ones for the dielectric response of a medium with the overscreening effect if the ion charge density is assumed to extend substantially beyond the cavity into the region occupied by the solvent.