On calculations of the ion hydration free energy within the framework of the RISM approach

The results of calculations of the hydration free energy for monovalent ions by the in- tegral equation method within the framework of the RISM approach with different sets of parameters of the Lennard-Jones potential are presented. The main goal of the study is to choose the optimum potential model providing reliable and the most accurate description of ion hydration thermodynamics and the fit to experimental data. The accuracy of calculations of the hydration free energy was tested using five equations available in the literature and five sets of parameters of the Lennard-Jones potential. The proper choice of parameters of the Lennard-Jones potential plays a significant role in RISM calculations of thermodynamic prop- erties, whereas the use of improved models in calculations of the hydration free energy does not always lead to more accurate results