A study was made of the structure and bonding of oxide clusters of the form, Si3Oy (where y was between 1 and 6), by using anion photo-electron spectroscopy and first-principles calculations. When y was between 1 and 3, the clusters reflected the sequential oxidation of Si3, and provided structural models for the oxidation of Si surfaces. When y was between 4 and 6, the clusters contained a central Si within a tetrahedral bonding environment; thus suggesting the onset of a bulk-like structure. It was suggested that the Si3O4 cluster (D2d) could provide a structural model for O-deficient defect sites in bulk SiO2.

L.S.Wang, J.B.Nicholas, M.Dupuis, H.Wu, S.D.Colson: Physical Review Letters, 1997, 78[23], 4450-3