Fragmentation of silicon microclusters: A molecular-dynamics study

Abstract

A detailed molecular-dynamics (MD) study has been performed to (i) enumerate ground-state and finite-temperature structures and (ii) investigate the nature of fragmentation for ${\mathrm{Si}}_{\mathrm{N}}$ clusters (N=2–14), using the Stillinger-Weber three-body interaction potential. We investigate all underlying mechanically stable structures visited by the system in the equilibrium state. Results indicate that the presence of magic numbers, unusually stable finite-temperature clusters ${\mathrm{Si}}_4$, ${\mathrm{Si}}_6$, and ${\mathrm{Si}}_{10}$ as determined by the photofragmentation experiment of Bloomfield, Freeman, and Brown is dependent upon the topology and energetics of high-energy bound structures rather than upon the structure and ground-state energies at zero temperature.