title: Long-ranged contributions to solvation free energies from theory and short-ranged models.
abstract: Long-standing problems associated with long-ranged electrostatic interactions have plagued theory and simulation alike. Traditional lattice sum (Ewald-like) treatments of Coulomb interactions add significant overhead to computer simulations and can produce artifacts from spurious interactions between simulation cell images. These subtle issues become particularly apparent when estimating thermodynamic quantities, such as free energies of solvation in charged and polar systems, to which long-ranged Coulomb interactions typically make a large contribution. In this paper, we develop a framework for determining very accurate solvation free energies of systems with long-ranged interactions from models that interact with purely short-ranged potentials. Our approach is generally applicable and can be combined with existing computational and theoretical techniques for estimating solvation thermodynamics. We demonstrate the utility of our approach by examining the hydration thermodynamics of hydrophobic and ionic solutes and the solvation of a large, highly charged colloid that exhibits overcharging, a complex nonlinear electrostatic phenomenon whereby counterions from the solvent effectively overscreen and locally invert the integrated charge of the solvated object.
authors.affiliation: Institute for Physical Science and Technology and Chemical Physics Program, University of Maryland, College Park, MD 20742; Institute for Computational Molecular Science, Temple University, Philadelphia, PA 19122;
authors.forename: Richard C
authors.initials: RC
authors.lastname: Remsing
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742; Department of Chemistry, James Franck Institute and Computation Institute, University of Chicago, Chicago, IL 60637.
authors.forename: Shule
authors.initials: S
authors.lastname: Liu
authors.affiliation: Institute for Physical Science and Technology and Chemical Physics Program, University of Maryland, College Park, MD 20742; Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742; jdw@umd.edu.
authors.forename: John D
authors.initials: JD
authors.lastname: Weeks
keywords: density functional theory; free energy calculations; hydrophobicity; mean field theory; solvation