Semiempirical LUC-INDO calculations on the effect of pressure on the electronic structure of diamond

A self-consistent LUC (large unit cell) formalism on the basis of semiempirical INDO (intermediate neglect of differential overlap) Hamiltonians has been used to study the electronic properties of diamond and to investigate the pressure dependence of these properties. The calculated properties are in good agreement with the experiments except the conduction-band width. The increase of pressure on diamond is predicted to cause the following effects; an increase of the valence and conduction-band widths with a decrease of the direct bandgap, an increase of the electronic occupation probability for the p-orbital with a decrease of this probability for the s-orbital, and a decrease of the X-ray scattering factor. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.