A variational approach to nucleation simulation

TL;DR

This paper introduces a variational enhanced sampling method based on classical nucleation theory to simulate the nucleation process in supersaturated Lennard-Jones vapors, overcoming time scale limitations of traditional methods.

Contribution

The paper applies a variational bias potential approach, grounded in classical nucleation theory, to improve simulation of nucleation rates in complex systems.

Findings

Successful application of the method to Lennard-Jones vapor nucleation

Overcomes free energy barrier challenges in simulations

Provides a pathway for calculating nucleation rates in various systems

Abstract

We study by computer simulation the nucleation of a supersaturated Lennard-Jones vapor into the liquid phase. The large free energy barriers to transition make the time scale of this process impossible to study by ordinary molecular dynamics simulations.Therefore we use a recently developed enhanced sampling method [Valsson and Parrinello, Phys. Rev. Lett. 113, 090601 (2014)] based on the variational determination of a bias potential. We differ from previous applications of this method in that the bias is constructed on the basis of the physical model provided by the classical theory of nucleation. We examine the technical problems associated with this approach. Our results are very satisfactory and will pave the way for calculating the nucleation rates in many systems.