Electronic structures and geometry of the Al12Si cluster solid

The electronic structures and geometry of a solid assembled out of cubic cl ose packing of Al12Si clusters have been studied with an ab initio pseudopo tential method and within the local density functional theory. Both the lat tice constant of the solid formed and the atomic geometry of the clusters i n it have been optimized through the ab initio method without adjustable va riables. Our results show that the crystal composed of Al12Si clusters is a metal rather than a semiconductor. Interactions between Al12Si clusters in the solid are strong and the clusters are no longer inert under crystal fi eld.