Dynamics and thermodynamics of decay in charged clusters

TL;DR

This paper introduces a novel method to quantify charge-driven instabilities in clusters through equilibrium simulations, revealing how charge influences decay modes and rates in Lennard-Jones clusters with Coulomb interactions.

Contribution

The study presents a new approach for assessing cluster stability without assuming decay modes, and provides a comprehensive analysis of charge effects on decay processes in model clusters.

Findings

Rate constants for particle ejection increase smoothly with charge.

Fission becomes more probable as total charge increases, competing with particle ejection.

Fission rate constants are more sensitive to charge than ejection rates.

Abstract

We propose a method for quantifying charge-driven instabilities in clusters, based on equilibrium simulations under confinement at constant external pressure. This approach makes no assumptions about the mode of decay and allows different clusters to be compared on an equal footing. A comprehensive survey of stability in model clusters of 309 Lennard-Jones particles augmented with Coulomb interactions is presented. We proceed to examine dynamic signatures of instability, finding that rate constants for ejection of charged particles increase smoothly as a function of total charge with no sudden changes. For clusters where many particles carry charge, ejection of individual charges competes with a fission process that leads to more symmetric division of the cluster into large fragments. The rate constants for fission depend much more sensitively on total charge than those for ejection of individual particles.