A model for the fragile-to-strong transition in water

TL;DR

This paper presents a model explaining the fragile-to-strong transition in supercooled water around 220 K, based on competing local structures and configurational entropy, aligning with behaviors seen in fragile glass-formers.

Contribution

It introduces a novel model linking local structural competition and entropy to water's fragile-to-strong transition, providing a unified explanation for observed behaviors.

Findings

High-temperature behavior resembles fragile glass-formers.

Low-temperature strong behavior linked to local structural entropy.

Model successfully explains the fragile-to-strong transition in water.

Abstract

A model based on the existence of two different competing local structures in water is described. It is shown that it can explain the transition between fragile and strong behavior that supercooled water has around 220 K. The high temperature behavior is similar to that observed in standard fragile glass-formers. The strong behavior at low temperatures is associated with the existence of a remanent configurational entropy coming from the possibility of locally choosing between the two possible environments.