Entropy behavior in cluster melting

摘要

We analyze the configurational excitation of a cluster for both a microcanonical and a canonicalensemble of atoms and apply this analysis to the Lennard-Jones cluster of 13 atoms. Dividing thecluster excitations into configurational and thermal classes, we evaluate the anharmonicitycoefficient of atomic vibrations and the entropy jump as a function of temperature on the basis ofcomputer simulations of the Lennard-Jones 13-atom cluster as a canonical and a microcanonicalensemble of atoms. This analysis shows the role of anharmonicity of atomic vibrations and exhibitsthe importance of the temperature dependence of the entropy jump in the range of phase coexistencefor cluster thermodynamics.