On Finite-Size Corrections to the Free Energy of Ionic Hydration

• Published in: The journal of physical chemistry. B Vol. 101; no. 29; pp. 5622 - 5623
• Main Authors: Figueirido, Francisco, Del Buono, Gabriela S, Levy, Ronald M
• Format: Journal Article
• Language: English
• Published: American Chemical Society 17.07.1997
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp970882x

Efforts to compare thermodynamic predictions of simulations with experiment have been thwarted by the approximations used in modeling the long-range electrostatic interactions. In a recent article Hummer et al. proposed an explicit formula that accounts for most of the finite-size effect in simulations of ion charging using periodic boundary conditions. In this Letter we have verified the numerical results of Hummer et al. and we provide a simple theoretical argument that explains why the solvent polarization free energy contains a contribution that largely cancels the lattice self-energy. The cancellation depends on the fact that the solvent is a high dielectric. We propose a finite size correction formula that can be applied in both the low and high dielectric limits.