Slater-Koster parametrization for Si and the ideal-vacancy calculation

A Slater-Koster Hamiltonian for Si is constructed using four (one $s$ and three $p$) orthogonal orbitals per site. This Hamiltonian reproduces reasonably accurately the empirical pseudopotential band structure not only for the valence but for the conduction band as well. It also determines correctly the position of the bound level of an unreconstructed vacancy demonstrating thus that the effects of electronic self-consistency are minor.