A short-range metastable defect in the double layer ice

TL;DR

This paper reports a metastable localized defect in double layer ice on Au(111), characterized by 5- and 7-membered rings, which remains stable and can form during ice growth without altering hydrogen bonds.

Contribution

It identifies a specific metastable defect structure in double layer ice and analyzes its stability and formation conditions, advancing understanding of ice defects at the molecular level.

Findings

The defect involves minimal molecular displacement of 0.08 Å.

The defect causes a 3.27% change in interaction energy.

The defect can form during ice growth, not just post-growth.

Abstract

Although the phase of water has extensively investigated whether there exists a defect distorting only locally the structure still under debate. Here we report a localized 5775 defect phase presented in the double layer ice on the Au (111) surface, which is a metastable structure with 5- and 7-membered rings compared with a perfect hexagonal one. Without altering the total number of the hydrogen bonds of the ice, the defect only introduces 0.08 {\AA} molecular displacement and 3.27% interaction energy change outside the defected area. Such defect also exists without Au support but causes a larger lattice relaxation or smaller interaction energy change. The excessively high barrier as well as the low quantum tunneling and thermodynamic probabilities hinder the formation of the defect by post-grown isomerization from the perfect to the defected structure. This finding indicates that the defected ice is stable, and the defect can be formed during the ice growth stage.