Calculation of Magic Numbers and the Stability of Small Si Clusters.

We present calculations of the equilibrium structures and cohesive energies for Si clusters up to the size n = 11. No open structures and no diamond lattice fragments are found. Especially stable structures for n = 6 and 10 coincide with experimentally observed magic numbers. Worked performed while a member of Dept. 11154, AT&T Bell Laboratories. Present and Permanent Address: Institute for Theoretical Physics, Freie Universitat Berlin, Arnimallee 14, D- 1000 Berlin 33, W.-Germany