Tight-binding model with intra-atomic matrix elements

We present a tight-binding model for silicon which incorporates two-center intra-atomic parameters. The model is fitted to density-functional-theory band structures for silicon in the diamond structure over a number of volumes. It is shown that with only a two-center, orthogonal basis, reasonable total energies can be obtained for many different structures. Thus it eliminates the need to use structure-dependent terms in the total-energy model.