Electron Diffraction of Water in No Man's Land

TL;DR

This study introduces a rapid electron diffraction method to analyze supercooled water's structure before crystallization, revealing a smooth transition towards amorphous ice and aiding understanding of water's anomalies.

Contribution

The paper presents a novel experimental approach to characterize deeply supercooled water's structure before crystallization occurs.

Findings

Water's structure evolves smoothly upon cooling.

Approaches to amorphous ice are identified.

Method narrows explanations for water anomalies.

Abstract

A generally accepted understanding of the anomalous properties of water will only emerge if it becomes possible to systematically characterize water in the deeply supercooled regime, from where the anomalies appear to emanate. This has largely remained elusive because water crystallizes rapidly between 160 K and 232 K. Here, we present an experimental approach to rapidly prepare deeply supercooled water at a well-defined temperature and probe it with electron diffraction before crystallization occurs. We show that as water is cooled from room temperature to cryogenic temperature, its structure evolves smoothly, approaching that of amorphous ice just below 200 K. Our experiments narrow down the range of possible explanations of the origin for the water anomalies and open up new avenues for studying supercooled water.