Influence of sample preparation on the transformation of low-density to high-density amorphous ice: An explanation based on the Potential Energy Landscape

TL;DR

This study uses computer simulations to show that the sharpness of the amorphous ice transformation depends on how the low-density amorphous ice is prepared, linking it to the potential energy landscape of the system.

Contribution

It demonstrates that the transformation behavior of amorphous ice can be predicted based on the initial sample's position in the potential energy landscape, unifying experimental and simulation results.

Findings

Transformation sharpness correlates with initial inherent structure energy.

Preparation method influences the potential energy landscape position.

Results are consistent across different preparation procedures.

Abstract

Experiments and computer simulations of the transformations of amorphous ices display different behavior depending on sample preparation methods, and on the rates of change of temperature and pressure to which samples are subjected. In addition to these factors, simulation results also depend strongly on the chosen water model. Using computer simulations of the ST2 water model, we study how the sharpness of the compression-induced transition from low-density amorphous ice (LDA) to high-density amorphous ice (HDA) is influenced by the preparation of LDA. By studying LDA samples prepared using widely different procedures, we find that the sharpness of the LDA-to- HDA transformation is correlated with the depth of the initial LDA sample in the potential energy landscape (PEL), as characterized by the inherent structure energy. Our results show that the complex phenomenology of the amorphous ices reported in experiments and computer simulations can be understood and predicted in a unified way from a knowledge of the PEL of the system.