Ab Initio Investigation of Ionic Hydration With the Polarizable Continuum Model

The formulation of an ab initio method for the quantification of the energetics of ionic hydration is reviewed from the viewpoint of thermodynamics and statistical mechanics. The numerical approach, termed as the Polarizable Continuum Model, solves the exact quantum mechanical problem for the solute coupled with the electrostatic problem of the solvent, the latter being described as an effective continuous medium. The results show that the method can reproduce the experimental values of solvation energy for 3 cations and 3 anions by using only one adjustable parameter (scaled ionic radius) and can therefore be used in the furthter study of energetics and structure of hydrated ions.