Quantum Dielectric Theory of Electronegativity in Covalent Systems. II. Ionization Potentials and Interband Transition Energies

We construct a dielectric two-band model which describes and predicts ionization potentials and electronic band structures of binary compounds $A_N{B}_{8-N}$. Only the density and dielectrically defined electronegativity difference are required as input data. The method is applied to 19 tetrahedrally coordinated crystals with excellent results. Predictions are also made for 18 other tetrahedrally coordinated crystals. The extension to octahedral coordination is discussed, and direct band gaps are calculated for 28 such crystals. It is also proposed that crystal structure and phase transitions can be predicted using this method.