Melting of aluminium clusters

TL;DR

This study investigates the melting behavior of aluminium clusters with sizes 49 to 62 using two different interatomic potentials, revealing significant differences and limitations in current models' ability to match experimental observations.

Contribution

It compares two interatomic potentials' predictions for aluminium cluster melting, highlighting their differences and shortcomings in reproducing experimental size-dependent melting transitions.

Findings

Glue potential shows smooth heat capacity curves with anomalies at specific sizes.

Gupta potential exhibits sharp peaks indicating first-order-like melting transitions.

Neither model fully captures the experimentally observed size dependence of melting.

Abstract

The melting of Al clusters in the size range 49 <= N <= 62 has been studied using two model interatomic potentials. The results for the two models are significantly different. The glue potential exhibits a smooth relatively featureless heat capacity curve for all sizes except for N = 54 and N = 55, sizes at which icosahedral structures are favoured over the polytetrahedral. Gupta heat capacity curves, instead, show a well-defined peak that is indicative of a first-order-like transition. The differences between the two models reflect the different ground-state structures, and neither potential is able to reproduce or explain the size dependence of the melting transition recently observed in experiments.