Structural Transitions and Global Minima of Sodium Chloride Clusters

TL;DR

This paper investigates the structural transitions and global energy minima of sodium chloride clusters, revealing unique deformation mechanisms at the nanoscale and comparing potential energy models.

Contribution

It identifies the atomic rearrangement pathways in NaCl clusters and compares empirical potentials, highlighting size-dependent mechanical properties.

Findings

Nanocrystals deform via slip on {110} planes, unlike bulk crystals.

Reaction pathways between isomers of (NaCl)35Cl- are characterized.

Global minima are compared across different empirical potentials.

Abstract

In recent experiments on sodium chloride clusters structural transitions between nanocrystals with different cuboidal shapes were detected. Here we determine reaction pathways between the low energy isomers of one of these clusters, (NaCl)35Cl-. The key process in these structural transitions is a highly cooperative rearrangement in which two parts of the nanocrystal slip past one another on a {110} plane in a <1-10> direction. In this way the nanocrystals can plastically deform, in contrast to the brittle behaviour of bulk sodium chloride crystals at the same temperatures; the nanocrystals have mechanical properties which are a unique feature of their finite size. We also report and compare the global potential energy minima for (NaCl)NCl- using two empirical potentials, and comment on the effect of polarization.