The thickness of a liquid layer on the free surface of ice as obtained from computer simulation

TL;DR

This study uses molecular dynamics simulations with four water models to analyze the formation and thickness of liquid layers on different ice surfaces below melting temperature, revealing temperature and plane-dependent behaviors.

Contribution

It provides a comparative analysis of liquid layer formation on ice surfaces across multiple water models and planes, highlighting temperature effects and model consistency.

Findings

Liquid layers form on all ice planes below melting point.

Layer thickness increases with temperature.

Thinner layers are observed on more complex planes.

Abstract

Molecular dynamic simulations were performed for ice Ih with a free surface by using four water models, SPC/E, TIP4P, TIP4P/Ice and TIP4P/2005. The behavior of the basal plane, the primary prismatic plane and of the secondary prismatic plane when exposed to vacuum was analyzed. We observe the formation of a thin liquid layer at the ice surface at temperatures below the melting point for all models and the three planes considered. For a given plane it was found that the thickness of a liquid layer was similar for different water models, when the comparison is made at the same undercooling with respect to the melting point of the model. The liquid layer thickness is found to increase with temperature. For a fixed temperature it was found that the thickness of the liquid layer decreases in the following order: the basal plane, the primary prismatic plane, and the secondary prismatic plane. For the TIP4P/Ice model, a model reproducing the experimental value of the melting temperature of ice, the first clear indication of the formation of a liquid layer appears at about -100 Celsius for the basal plane, at about -80 Celsius for the primary prismatic plane and at about -70 Celsius for the secondary prismatic plane.