Universal bridge functional for infinitely diluted solutions: a case study for Lennard-Jones spheres of different diameter

TL;DR

This paper introduces a universal bridge functional for the Ornstein-Zernike equation, parameterized by molecular dynamics data, improving the accuracy of radial distribution functions for dilute Lennard-Jones solutions.

Contribution

The paper proposes a universal, size-ratio dependent bridge functional for the OZ equation, validated across different Lennard-Jones systems, enhancing RDF predictions.

Findings

Bridge functional can be parameterized with an exponential function based on size ratio.

Including the bridge functional improves RDF predictions compared to HNC closure.

The approach is effective for infinitely diluted Lennard-Jones solutions.

Abstract

In the paper we propose an universal bridge functional for the closure of the Ornstein-Zernike (OZ) equation for the case of infinitely diluted solutions of Lennard-Jones shperes of different size in the Lennard-Jones fluid. Bridge functional is paprameterized using the data of the Molecular Dynamics (MD) simulations. We show that for all investigated systems the bridge functional can be efficiently papameterized with the exponential function which depends only on the ratio of sizes of the solute and solvent atoms. To check the parameterization we solve the OZ equation with the closure which includes the parametrized functional and with the closure without the bridge functional (Hyper-netted chain closure). We show that introducing the bridge functional allows to obtain radial distribution functions (RDFs), which are close to the MD results and essentially improve predictions of the location and height of the first peak of the RDF.