A simple model of atomic interactions in noble metals based explicitly on electronic structure

A total energy tight-binding model with a basis of just one s state per ato m is introduced. It is argued that this simplest of all tight-binding model s provides a surprisingly good description of the structural stability and elastic constants of noble metals. By assuming inverse power scaling laws f or the hopping integrals and the repulsive pair potential, it is shown that the density matrix in a perfect primitive crystal is independent of volume , and structural energy differences and equations of state are then derived analytically. The model is most likely to be of use when one wishes to con sider explicitly and self-consistently the electronic and atomic structures of a generic metallic system, with the minium of computation expense. The relationship to the free-electron jellium model is described. The applicabi lity of the model to other metals is also considered briefly.