Deriving Reliable Nucleation Rates from Metadynamics Simulations: Application to Yukawa Fluids

TL;DR

This paper develops a method to accurately derive nucleation rates from metadynamics simulations, demonstrating its effectiveness on Yukawa fluids and validating predictions against reference data.

Contribution

It introduces a specific postprocessing procedure for metadynamics data to reliably calculate nucleation free energy barriers and rates, with a focus on local collective variables.

Findings

Accurate nucleation rates can be derived from metadynamics simulations.

The method successfully reproduces low-temperature nucleation data for Yukawa fluids.

Physically-motivated fitting validates the predictive power of the approach.

Abstract

In order to solidify the usefulness of metadynamics in studying nucleation of crystals from supercooled liquids, we provide a specific procedure to calculate nucleation free energy barriers. After a pedagogical review of the important elements of classical nucleation theory and how metadynamics is used to find nucleation free energy barriers, we explain the benefits of local collective variables over more common global collective variables. We show how a metadynamics free energy barrier must be carefully postprocessed so that classical nucleation theory can be applied to calculate nucleation rates. We apply our procedure to a Yukawa plasma and show that a particular physically-motivated fit to metadynamics data reproduces low-temperature reference data, justifying the usefulness of metadynamics to predict nucleation rates and the nucleation critical temperature.