Optimized structures of Si-28 and Ba@Si-28 clusters: Ab initio study

摘要

First-principle electronic structure calculations are carried out for the Si-28 and endohedral Ba@Si-28 clusters, which are components of the clusters in the silicon clathrate II. We obtain the structurally optimized cage structures of the Clusters and the exohedral binding nature of Si atom on the Ba@Si-28 clusters, The hollow Si-28 cluster relaxes into the Si-24-like cluster in the clathrate I, having four exohedral Si atoms outside the hexagon. The hexagons on the Ba@Si-28 cluster deforms into chair-type with relaxation. The exohedral Si atom is the most stable at the edge center near the top that forms three pentagons. We propose a mechanism of the growth of the clathrates. (C) 2002 Wiley Periodicals, Inc. [References: 14]