# Homogeneous nucleation of ice

## TL;DR

This study uses atomistic simulations to explore the microscopic details of ice nucleation, revealing the structure of critical nuclei and confirming the role of tetrahedral water coordination in the process.

## Contribution

It introduces a novel simulation approach with collective variables to study water-to-ice transitions at the atomic level.

## Key findings

- Water freezes into stacking disordered ice with TIP4P/Ice model
- Critical nuclei exhibit specific structural features
- Nucleation is preceded by increased tetrahedral coordination

## Abstract

Ice nucleation is a process of great relevance in physics, chemistry, technology and environmental sciences, much theoretical and experimental efforts have been devoted to its understanding, but still it remains a topic of intense research. We shed light on this phenomenon by performing atomistic based simulations. Using metadynamics and a carefully designed set of collective variables, reversible transitions between water and ice are able to be simulated. We find that water freezes into a stacking disordered structure with the all-atom TIP4P/Ice model, and the features of the critical nucleus of nucleation at the microscopic level are revealed. Our results are in agreement with recent experimental and other theoretical works and confirm that nucleation is preceded by a large increase in tetrahedrally coordinated water molecules.