Wall-liquid and wall-crystal interfacial free energies via thermodynamic integration: A molecular dynamics simulation study

TL;DR

This study introduces a molecular dynamics simulation method using thermodynamic integration to accurately compute interfacial free energies between Lennard-Jones systems and structured walls, considering different phases and parameters.

Contribution

It presents a novel thermodynamic integration approach to evaluate wall-liquid and wall-crystal interfacial free energies in molecular simulations.

Findings

Interfacial free energy depends on wall potential, density, and orientation.

Conditions for partial wetting of Lennard-Jones crystal on flat walls are identified.

Method effectively distinguishes between different interfacial states.

Abstract

A method is proposed to compute the interfacial free energy of a Lennard-Jones system in contact with a structured wall by molecular dynamics simulation. Both the bulk liquid and bulk face-centered-cubic crystal phase along the (111) orientation are considered. Our approach is based on a thermodynamic integration scheme where first the bulk Lennard-Jones system is reversibly transformed to a state where it interacts with a structureless flat wall. In a second step, the flat structureless wall is reversibly transformed into an atomistic wall with crystalline structure. The dependence of the interfacial free energy on various parameters such as the wall potential, the density and orientation of the wall is investigated. The conditions are indicated under which a Lennard-Jones crystal partially wets a flat wall.