Environment-dependent tight-binding potential model.

We present a tight-binding model which goes beyond the traditional two-center approximation and allows the hopping parameters and the repulsive energy to be dependent on the binding environment. Using carbon as an example, we show that the approach improves remarkably the transferability of the tight-binding model. The properties of the higher-coordinated metallic structures are well described by the model in addition to those of the lower-coordinated covalent structures.