Geometries and electronic properties of [formula omitted] clusters

Abstract

The equilibrium geometries and electronic properties of Na m Si n ( m + n ⩽ 7 ) clusters have been studied by using density functional theory at the B3LYP/6-311+G( d) level. The ground state structures of Na m Si n clusters can be obtained by adding one Na atom to Na m - 1 Si n clusters, and the Na atom locates on the site which maximally tends to form Na Si bonds. The Si-rich clusters are more stable than Na-rich clusters with the same number of atoms. The Si Si bond is stronger than the Na Si bond, and the latter is stronger than the Na Na bond. The vertical ionization potentials of Na m Si n clusters obtained by B3LYP are in good agreement with the experimental values available. For such a certain cluster size ( m + n = 4 , 5 , 6 , 7 ) , the energy gaps of the most stable Na m Si n clusters show odd–even oscillation with changing m, the clusters with odd Na atoms exhibit stronger chemical reactivity than those with even Na atoms.