The molecular statistical theory of infinitely dilute solutions based on the ion-dipole model with Lennard-Jones interaction

The group expansions obtained in the collective variable method are applied to calculate the equilibrium thermodynamic properties of non-polar gases and simple ions dissolved in a liquid polar solvent at infinite dilution of the solute. The non-electrostatic contribution is calculated in the high temperature approximation whereas the electrostatic contribution is calculated from the ion-dipole model in the random phase approximation. The hard sphere model (Mansoori-Carnahan-Starling-Leland approximation) has been chosen as the reference system. Analytical expressions for the thermodynamic functions such as solvation chemical potential, entropy, enthalpy and heat capacity, as well as the partial molar volume, compressibility and expansibility are given. A comparison of the theoretically predicted and experimental values of thermodynamic properties at infinite dilution of aqueous solutions of non-polar gases and simple ions is reported.