Convergence of the Chemical Potential in Aqueous simulations

Abstract

The chemical potential of a sphere in water is calculated using a molecular dynamics simulation. The convergence of a continuous sampling method is examined. Free energy calculations for forming a cavity or methane site in water with a thermodynamic integration are found to be strongly dependent on total simulation time length out to hundreds of picoseconds. The implications of insufficient sampling are given and related to relaxation time scales in the solvent about the solute in an Eisenberg-Kauzmann like analysis. Implications for more complex liquids are discussed.