Simulations of an ion in spherical geometry were set up by replacing the central water molecule in the pre-equilibrated cubic box with a Na + or a Cl -ion. The ion was positionally constrained to the box center. Some simulations of ions with the same Lennard-Jones parameters but higher charge magnitudes (Na 2+ , Na 3+ , Cl 2-and Cl 3-) were carried out in a similar fashion. There also, the applied correction potential was constructed for the pure-water system. Sampling was carried out for 10 ns. Free-energy calculations also relied on 1 ns simulations performed with |q| = 0.05, 0.5 and 0.75 e ion charge (instead of the full charge).