S. A. Blundell, SPSMS, UMR-E CEA/UJF-Grenoble 1, INAC, Grenoble, F-38054, France
Soumyajyoti Haldary, Centre for Modeling and Simulation, University of Pune, Ganeshkhind, Pune 411 007, India and Department of Physics, University of Pune, Ganeshkhind, Pune 411 007, India.
D. G. Kanherez, Department of Physics, University of Pune, Ganeshkhind, Pune 411 007, India.

Dated: March 2, 2011

Abstract. We determine the structure and melting behavior of supported metallic clusters using an ab intio density-functional-based treatment of intracluster interactions and an approximate treatment of the surface as an idealized smooth plane yielding an eective Lennard-Jones interaction with the ions of the cluster. We apply this model to sodium clusters containing from 4 to 22 atoms, treating the cluster-surface interaction strength as a variable parameter. For a strong cluster-surface interaction, the clusters form monolayer structures; comparisons with calculations of structure and dissociation energy performed with a classical Gupta interatomic potential show clearly the role of quantum shell eects in the metallic binding in this case, and evidence is presented that these shell eects correspond to those for a conned two-dimensional electron gas. The melting behavior of a supported Na20 cluster is considered in detail using the model. Some qualitative similarities are observed in the melting dynamics between the density-functional and Gupta treatments of the cluster, involving either interlayer hops or in-plane melting according to the cluster-surface interaction strength, but there are quantitative dierences in the specic-heat curves and melting temperatures observed.

In: Phys. Rev. B 84, 075430 (2011)