ION SIZES AND FINITE-SIZE CORRECTIONS FOR IONIC-SOLVATION FREE-ENERGIES

Free energies of ionic solvation calculated from computer simulations exhibit a strong system size dependence. We perform a finite-size anal ysis based on a dielectric-continuum model with periodic boundary cond itions. That analysis results in an estimate of the Born ion size. Rem arkably, the finite-size correction applies to systems with only eight water molecules hydrating a sodium ion and results in an estimate of the Born radius of sodium that agrees with the experimental value. (C) 1997 American Institute of Physics.