Alkali halides in water: Ion-solvent correlations and ion-ion potentials of mean force at infinite dilution

Using the specialization of the extended RISM equation to infinitely dilute systems, we have calculated correlation functions and interionic potentials of mean force for a set of models corresponding to the first few alkali halides in water. From the results obtained at infinite dilution we calculate the lowest order corrections to the solution properties of the ions. Higher concentrations are explored by using the interionic potentials of mean force at infinite dilution as effective solvent mediated pair potentials. Our results indicate that certain thermodynamic properties, such as the mean activity coefficients and osmotic pressures, are quite sensitive to the details of both the theory and the potential models.