Improved association in a classical density functional theory for water

TL;DR

This paper enhances a classical density functional theory for water by integrating a more accurate radial distribution functional, leading to better hydrogen bonding predictions near solutes.

Contribution

The authors incorporate an improved radial distribution functional into the association term of a SAFT-based water model, enhancing hydrogen bonding accuracy.

Findings

Moderate change in density profiles around solutes

Large decrease in broken hydrogen bonds near solutes

Improved interface accuracy of the functional

Abstract

We present a modification to our recently published SAFT-based classical density functional theory for water. We have recently developed and tested a functional for the averaged radial distribution function at contact of the hard-sphere fluid that is dramatically more accurate at interfaces than earlier approximations. We now incorporate this improved functional into the association term of our free energy functional for water, improving its description of hydrogen bonding. We examine the effect of this improvement by studying two hard solutes: a hard hydrophobic rod and a hard sphere. The improved functional leads to a moderate change in the density profile and a large decrease in the number of hydrogen bonds broken in the vicinity of the solutes.We present a modification to our recently published SAFT-based classical density functional theory for water. We have recently developed and tested a functional for the averaged radial distribution function at contact of the hard-sphere fluid that is dramatically more accurate at interfaces than earlier approximations. We now incorporate this improved functional into the association term of our free energy functional for water, improving its description of hydrogen bonding. We examine the effect of this improvement by studying two hard solutes: a hard hydrophobic rod and a hard sphere. The improved functional leads to a moderate change in the density profile and a large decrease in the number of hydrogen bonds broken in the vicinity of the solutes.