A Classical Density-Functional Theory for Describing Water Interfaces

TL;DR

This paper introduces a classical density functional for water that combines FMT and SAFT-VR theories, accurately modeling water interfaces across scales with high computational efficiency.

Contribution

It presents a novel functional integrating FMT and SAFT-VR for water, capable of describing interfaces at multiple scales efficiently.

Findings

Reproduces water properties at various length scales and temperatures.

Efficient computationally, comparable to FMT alone.

Successfully applied to systems of hard rods and spheres in water.

Abstract

We develop a classical density functional for water which combines the White Bear fundamental-measure theory (FMT) functional for the hard sphere fluid with attractive interactions based on the Statistical Associating Fluid Theory (SAFT-VR). This functional reproduces the properties of water at both long and short length scales over a wide range of temperatures, and is computationally efficient, comparable to the cost of FMT itself. We demonstrate our functional by applying it to systems composed of two hard rods, four hard rods arranged in a square and hard spheres in water.