EQUILIBRIUM GEOMETRIES AND ELECTRONIC STRUCTURE OF SMALL SILICON MONOHYDRIDES CLUSTERS

Abstract

The geometries and energies of small silicon monohydride clusters ( Si 2 H – Si 10 H ) have been systematically investigated by density functional theory (DFT) scheme with DZP++ basis sets. Several possible geometric arrangements and electronic states have been considered for each cluster. The results on Si 2 H – Si 4 H are in good accordance with previous ab initio calculation. The geometry of ground state of Si 2 H is found to be a bridged C2v structure, and Si 3 H to be a bridged C2v, while Si 4 H a non-bridged Cs symmetry with 2A′ state. The non-bridged geometries of ground state of Si 5 H – Si 10 H have been found to be corresponding to C2v(2B1), C2v(2B1), C5v(2A1), Cs(2A′′) (have two types), C1 (not symmetry), and Cs(2A′), respectively. The results on Si 5 H , Si 6 H , Si 8 H and Si 9 H are different from previous calculations. Compared silicon clusters ( Si n) with silicon monohydrides ( Si n H ) clusters, the addition of a single hydrogen atom cannot cause great changes in the ground state geometries of Si 2, Si 3, Si 4, Si 7, Si 9, and Si 10 clusters, while in the ground state geometries of Si 5, Si 6 and Si 8 clusters the change is great. The dissociation energies calculated indicates that Si 4 H , Si 7 H , and Si 10 H clusters are less stable than others.