Generalizing The Mean Spherical Approximation as a Multiscale, Nonlinear Boundary Condition at the Solute--Solvent Interface

Abstract

In this paper we extend the familiar continuum electrostatic model with a perturbation to the usual macroscopic boundary condition. The perturbation is based on the mean spherical approximation (MSA), to derive a multiscale hydration-shell boundary condition (HSBC). We show that the HSBC/MSA model reproduces MSA predictions for Born ions in a variety of polar solvents, including both protic and aprotic solvents. Importantly, the HSBC/MSA model predicts not only solvation free energies accurately but also solvation entropies, which standard continuum electrostatic models fail to predict. The HSBC/MSA model depends only on the normal electric field at the dielectric boundary, similar to our recent development of an HSBC model for charge-sign hydration asymmetry, and the reformulation of the MSA as a boundary condition enables its straightforward application to complex molecules such as proteins.

arXiv comment14 pages, 2 figures

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Cited by in corpus (2)

• Dielectric continuum methods for quantum chemistry
• Predicting Solvation Free Energies and Thermodynamics in Polar Solvents and Mixtures Using a Solvation-Layer Interface Condition