Electronic structure of α-Al₂O₃

The author has calculated the electronic energy structure of alpha -alumina in corundum structure ( alpha -Al₂O₃) using a first principles extended tight-binding method. The interest in the electronic properties of alpha -Al₂O₃ is expanding because of well-documented interest in chemisorption of oxygen on aluminium and the oxidation of aluminium itself. To understand bonding in this compound the author has compared his results with the known electronic structure of alpha -quartz ( alpha -SiO₂). The latter has been investigated much more thoroughly and has similar properties to alpha -Al₂O₃. The authors have noted certain trends in going from alpha -Al₂O₃ to alpha -SiO₂. These trends are quite similar to those reported in a cluster model calculation on AlO₄ and SiO₄. The author has also calculated the total and orbital densities of states and have compared these with X-ray photoemission spectra. It has been found that the calculated results do not agree fully with the existing experimental data. The author also briefly comments on the controversial O-Al bond length for oxygen chemisorbed on Al(111).