Structure, fragmentation, and phonons in silicon microclusters

Molecular-dynamics simulations are performed to investigate structures, vibrational spectra, and fragmentation channels of silicon microclusters ranging in size from 32 to 52 atoms. Structural information is derived from pair-distribution functions, bond-angle distributions, and the structure and statistics of rings. Molecular-dynamics simulation results for energetics suggest that 33, 39, 45 and 51 atom clusters are highly stable. These magic-number clusters have predominantly five and six membered rings. With an increase in `temperature', most clusters tend to fragment by loosing one atom at a time. Vibrational densities of states of 32-52 atom silicon clusters show only minor deviations from the bulk behavior.