Free energy landscapes for homogeneous nucleation of ice for a monatomic water model

TL;DR

This study uses Monte Carlo simulations to analyze the free energy landscape of homogeneous ice nucleation from supercooled water with a monatomic model, confirming classical nucleation theory predictions.

Contribution

It provides detailed free energy profiles and nucleation barriers for ice formation using a monatomic water model, aligning with classical nucleation theory.

Findings

Nucleation free energy barrier is approximately 18 kT.

Critical nucleus size is about 85 ice particles.

Growth phase predominantly forms cubic ice clusters.

Abstract

We simulate the homogeneous nucleation of ice from supercooled liquid water at 220 K in the isobaric-isothermal ensemble using the MW monatomic water potential. Monte Carlo simulations using umbrella sampling are performed in order to determine the nucleation free energy barrier. We find the Gibbs energy profile to be relatively consistent with that predicted by classical nucleation theory; the free energy barrier to nucleation was determined to be ~18 kT and the critical nucleus comprised ~85 ice particles. Growth from the supercooled liquid gives clusters that are predominantly cubic, whilst starting with a pre-formed subcritical nucleus of cubic or hexagonal ice results in the growth of predominantly that phase of ice only.