The solvent mediated interaction potential between solute particles: Theory and applications

TL;DR

This paper develops a theoretical framework to compute solvent-mediated interaction potentials between solute particles, incorporating solvent fluctuations and many-body effects, with applications to the Asakura-Oosawa model.

Contribution

The paper introduces a self-consistent theory for solvent-mediated interactions that accounts for many-body effects and solvent fluctuations, advancing beyond previous simpler models.

Findings

Quantitative description of many-body effects on effective potential

Application to the Asakura-Oosawa model for various densities

Elucidation of solvent fluctuation influence on interaction range

Abstract

In this paper we develop a theory to calculate the solvent mediated interaction potential between solute particles dispersed in a solvent. The potential is a functional of the instantaneous distribution of solute particles and is expressed in terms of the solute-solvent direct pair correlation function and the density-density correlation function of the bulk solvent. The dependence of the direct pair correlation function on multi-point correlations of the solute distribution is simplified with a mean field approximation. A self consistent approach is developed to calculate the effective potential between solute particles, the solute-solvent and the solute-solute correlation functions. The significance of the solvent fluctuations on the range of the effective potential is elucidated. The theory is applied to calculate equilibrium properties of the Asakura-Oosawa (AO) model for several values of solute and solvent densities and for several values of the particles size ratio. The results give a quantitative description of many-body effect on the effective potential and on the pair correlation functions.