Premelting layer during ice growth: role of clusters

TL;DR

This study uses molecular dynamics simulations to explore how clusters on the premelting surface influence ice growth, revealing stable cluster distributions and growth mechanisms that connect microscopic structures to macroscopic behavior.

Contribution

It uncovers the formation and evolution of clusters on the premelting surface and links their distribution to different ice growth modes, advancing understanding of premelting and ice growth mechanisms.

Findings

Clusters form stable distributions influenced by growth rate

Bilayer-by-bilayer growth mode observed at high rates

Proposed 'cluster stacking' mechanism at lower growth rates

Abstract

The premelting plays an important role in ice growth, but there is a significant gap in our knowledge between the atomistic premelting surface structure and the macroscopic growth mechanism. In this work, using large-scale molecular dynamics simulation, we reveal the existence of clusters on premelting surface, as an intermediate feature bridging the gap. We show the spontaneous formation and evolution of clusters, and they form a stable distribution determined by the growth rate. We demonstrate how this stable distribution is related to the growth mode of ice, connected by the growth of clusters. We come to a bilayer-by-bilayer growth mode under simulation-reachable high growth rates, but another mechanism, namely "cluster stacking", is speculated to exist at lower growth rates. Our work builds a connection between the microscopic structure of premelting layer and the macroscopic growth of ice, making a step forward to the full understanding of premelting and ice growth.