Structures ofSi7H2m(m=1–7)clusters by global optimization

Abstract

Structures of ${\mathrm{Si}}_{7}{\mathrm{H}}_{2m}$ $(m=1--7)$ clusters are studied by a global search strategy using a genetic algorithm in combination with tight-binding potentials to describe the interatomic interactions. The low-energy structures obtained from the global search are further studied by ab initio calculations. Almost all the lowest-energy structures (except ${\mathrm{Si}}_{7}{\mathrm{H}}_{12}$) obtained from our present study are energetically more stable than those structures previously proposed. Using the lower-energy isomers from our calculations, the relationship between the geometric structures and energetic stabilities of the hydrogenated silicon clusters is also discussed.