Regularizing binding energy distributions and thermodynamics of hydration. Application to water modeled with classical and ab initio simulations

摘要

The high-energy tail of the distribution of solute-solvent interactionenergies is poorly characterized for condensed systems, but this tail region isof principal interest in determining the excess free energy of the solute. Weintroduce external fields centered on the solute to modulate the short-rangerepulsive interaction between the solute and solvent. This regularizes thebinding energy distribution and makes it easy to calculate the free energy ofthe solute with the field. Together with the work done to apply the field inthe presence and absence of the solute, we calculate the excess chemicalpotential of the solute. We present the formal development of this idea andapply it to study liquid water.