Molecular-dynamics analysis of morphological evolution of softly deposited Au nanoclusters.

The initial period following deposition of soft-landing Au clusters is investigated by classical molecular-dynamics simulation. The embedded-atom method potential is adopted for the interaction between Au atoms. Clusters of specified sizes are cut out of the bulk crystal structure. Whether a cluster equilibrated at a given temperature is in a solid state or in a liquid state is judged by tracking the trajectory of an atom in the cluster and by examining the radial distribution function. The deposition simulation reveals that there is an energy barrier in the morphological accommodation of a cluster to the substrate if the cluster is crystalline before deposition, and is equilibrated at a temperature different from that of the substrate. On the other hand, there is no energy barrier in the morphological accommodation of a cluster that is in a liquid state before deposition. Exceptionally, a crystalline cluster that is nearly at a melting temperature can accommodate itself smoothly to the substrate maintained at the same temperature without an energy barrier. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]