Instantaneous Normal Mode Analysis of Supercooled Water

TL;DR

This paper employs instantaneous normal mode analysis to explore the potential energy landscape of supercooled water, revealing how geometric properties influence dynamics and basin connectivity.

Contribution

It introduces a novel application of normal mode analysis to link local curvature and basin connectivity with water's dynamic behavior.

Findings

Diffusion constant correlates with the fraction of directions connecting minima.

Number of basins accessed relates to their connectivity.

Dynamics are governed by the geometric structure of configuration space.

Abstract

We use the instantaneous normal mode approach to provide a description of the local curvature of the potential energy surface of a model for water. We focus on the region of the phase diagram in which the dynamics may be described by the mode-coupling theory. We find, surprisingly, that the diffusion constant depends mainly on the fraction of directions in configuration space connecting different local minima, supporting the conjecture that the dynamics are controlled by the geometric properties of configuration space. Furthermore, we find an unexpected relation between the number of basins accessed in equilibrium and the connectivity between them.