Energy band structure of noble metals

The band energies of copper and gold have been calculated by the composite wave variational method at the symmetry points Γ, X and L of the Brillouin zone and the results for all the noble metals have been compared with the estimations of Cohen and Heine. It is found that at the zone face L of the Brillouin zone the p states are below the s states for copper and silver, but for gold the reverse is the case. The energy gaps in all cases, however, are not sufficient to show any contact between the Fermi surface and the zone face L. But the values of the effective mass are nearer to the experimental values than those of Cohen and Heine.