Ground State Geometries and Vibrational Spectra of Small Hydrogenated Silicon Clusters using Nonorthogonal Tight-Binding Molecular Dynamics

We report a systematic study of ground state structures, vibrational spectra cohesive energies and HOMO-LUMO gaps of small Si n H m clusters (n=1, 2 and m=1–6) and their deuterated derivatives based on the nonorthogonal tight-binding molecular dynamics scheme. The ground state structures have been obtained by using simulated annealing. The bond lengths, bond angles and the frequencies of normal modes are found to be in good agreement with available experimental data and ab initio calculations. Our calculation of cohesive energies indicate SiH 2 to be more stable than SiH 3 or SiH and Si 2 H 4, more stable than Si 2 H 3 or Si 2 H 5.