On the fragmentation of multiply charged sodium clusters

TL;DR

This paper investigates how multiply charged sodium clusters fragment at high energies using statistical simulations, revealing phase transition behaviors and negative specific heat phenomena characteristic of finite systems.

Contribution

It applies the MMMC statistical technique to sodium clusters, providing new insights into their fragmentation and phase transition properties at various charge states.

Findings

Caloric curves show a dip indicating negative specific heat.

Fragment distributions support a phase transition from liquid-like to vaporized states.

Results demonstrate charge-dependent fragmentation behavior.

Abstract

The fragmentation of multiply charged atomic sodium clusters of mass 200 is investigated using the Micro-canonical Metropolis Monte Carlo (MMMC) statistical technique for excitation energies up to 200 eV and for cluster charges up to $+9e$. In this work we present caloric curves and charged and uncharged fragment mass distributions for clusters with charges 0, 2, and 4. The caloric curves show a dip at the critical point implying a negative specific heat, as expected for finite systems, while the fragment mass distributions corroborate the picture of a phase transition from one dominant liquid-like cluster to complete vaporization.