Fragmentation Phase Transition in Atomic Clusters II - Coulomb Explosion of Metal Clusters -

TL;DR

This paper investigates the phase transition behavior in charged metal clusters during Coulomb explosion, revealing how increasing charge affects fragmentation modes and the disappearance of phase transition phenomena.

Contribution

It introduces a detailed analysis of polarization effects and identifies how charge influences the fragmentation phase transition in sodium clusters.

Findings

Phase transition shifts to lower energies with increased charge.

Complete decay into small fragments occurs at high charges.

Fragmentation phase transition disappears beyond Z=8 charges.

Abstract

We discuss the role and the treatment of polarization effects in many-body systems of charged conducting clusters and apply this to the statistical fragmentation of Na-clusters. We see a first order microcanonical phase transition in the fragmentation of $Na^{Z+}_{70}$ for Z=0 to 8. We can distinguish two fragmentation phases, namely evaporation of large particles from a large residue and a complete decay into small fragments only. Charging the cluster shifts the transition to lower excitation energies and forces the transition to disappear for charges higher than Z=8. At very high charges the fragmentation phase transition no longer occurs because the cluster Coulomb-explodes into small fragments even at excitation energy $\epsilon^* = 0$.