Transferable tight-binding model for palladium and silver

A transferable orthogonal tight-binding (TB) model for Pd and Ag is developed by the simultaneous fit to the energy levels and total energies of a number of clusters of up to 55 atoms in size, as well as the total energies of fcc and bcc structures all obtained from density functional calculations. The effect of the environment is included by incorporating two-center intra-atomic parameters and local environment dependent on-site atomic energy levels. The scheme is tested by comparing its predictions of both bulk and cluster properties with those from ab initio calculations. It is then used to study the behavior of relaxed icosahedral and cubo-octahedral clusters of up to 201 atoms in size.