A first-principles study of oxidation pattern in magic Si 7 cluster

Abstract

Oxidation pattern of the magic cluster Si 7 was studied by first-principles calculations of Si 7O n ( n = 1–14) clusters. The lowest-energy structures of the Si-rich clusters consist of a pure Si fragment and an oxide fragment. The oxidation is found to extend from one edge throughout the whole cluster as the number of the oxygen atoms increases. Fragmentation energy analysis shows that the Si-rich clusters can often dissociate into a small pure Si n ( n = 2–6) cluster and a silicon oxide fragment. The O-rich clusters tend to separate into a SiO molecule and a silicon oxide fragment, except for Si 7O 14 which can easily lose an oxygen molecule in the fragmentation. The ionic clusters Si 7 O n ± ( n = 1–14) were also studied.