Tight-binding model for transition metals: From cluster to solid - art. no. 125105

A transferable tight-binding (TB) model is presented within an orthogonal s pd basis set that incorporates two-center intra-atomic parameters as well a s local environment dependent on-site atomic energy levels. The parametriza tion of the model is determined by a simultaneous fit to the energy levels and total energies obtained from density-functional calculations for a numb er of cluster structures of up to 55 in size, although other bulk data coul d also be used in the fit. We have applied the method to rhodium and calcul ated the bulk properties. The equilibrium lattice constant, structural ener gy difference, elastic constants, surface energies, and vacancy formation e nergies are obtained and these are in reasonably good agreement with both b ulk local-density functional theory and experiment. The two-center intra-at omic parameters are usually ignored in TB calculations. This paper demonstr ates that it is essential that such terms be included in the calculation on clusters.