A generalization of surface reconstruction arguments was considered, for the structure of intermediate-size Si clusters, which led to model geometries for the sizes: 33, 39 (two isomers), 45 (two isomers), 49 (two isomers), 57 and 61 (two isomers). The common feature of all of the models was a structure that closely resembled the most stable reconstruction of Si surfaces, surrounding a core of bulk-like tetrahedrally bonded atoms. The energetics and electronic structures of these models were investigated using first-principles density-functional theory calculations. These models could be useful in understanding experimental results on the reactivity of Si clusters and their shape as deduced from mobility measurements.

Surface-Reconstruction-Induced Geometries of Si Clusters. E.Kaxiras: Physical Review B, 1997, 56, 13455-63