Dynamics and thermodynamics of decay in charged clusters

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.

Keywords:

• charged clusters
• instability
• simulation
• Lennard-Jones
• Rayleigh limit

Acknowledgements

The authors thank Dr Florent Calvo for helpful discussions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

SJG is grateful to Durham University's Institute for Advanced Research Computing for a summer seedcorn grant. DAB is indebted to CNRS (Centre National de la Recherche Scientifique) for the award of a Chaire d'excellence. Travel for MPG and MAM associated with this collaboration was supported by the Alliance Programme of the British Council and the French Ministère des Affaires Etrangères.