Partial molar volumes of aqua ions from first principles
Résumé
Partial molar volumes of ions in water solution are calculated through pressures obtained fromab initio molecular dynamics simulations. The definition of pressure in charged systems subject toperiodic boundary conditions requires access to the variation of the electrostatic potential upon achange of volume. We develop a scheme for calculating such a variation in liquid systems by settingup an interface between regions of different density. This also allows us to determine the absolutedeformation potentials of liquid water. With the properly defined pressures, we yield partial molarvolumes of a series of aqua ions in very good agreement with experimental values.