  We use molecular dynamics with an embedded atom potential to study the
behavior of palladium nanoclusters near the melting point in the microcanonical
ensemble. We see transitions from both fcc and decahedral ground state
structures to icosahedral structures prior to melting over a range of cluster
sizes. In all cases this transition occurs during solid-liquid phase
coexistence and the mechanism for the transition appears to be fluctuations in
the molten fraction of the cluster and subsequent recrystallization into the
icosahedral structure.
