Absolute Hydration Free Energies of Ions Under Periodic Boundary Conditions

The additive empirical force field of a monatomic ion is composed of the charge and the Lennard-Jones (LJ) parameters, i. e., the well-depth parameter, ε, and the distance parameter, Rmin, at which the potential reaches the minimum. A set of LJ parameters for monocations have been developed by utilizing molecular dynamics simulations under a solvent boundary potential (SBP). A full account of the force field development is in progress and this communication addresses consideration of the air-water phase potential in calculating the absolute free energy of hydration by calculating free energies of hydration, ΔGhyd, in the presence of periodic boundary conditions (PBC)