Optical Absorption in Noble Metals

The sharp absorption peaks appearing at about 0.52 µ and 0.29 µ for Cu and Ag, respectively, are explained by the interband transitions from the d band to the conduction band. The energy spectra of the d band and the conduction band are expressed by simple functions consistent with the calculated band structures. It is shown that the wave-length dependence of the calculated conductivity agrees fairly well with experiments. From the results of the experiments about the change of the electronic specific heats and the shift of the absorption edge in alloying Zn in Cu, the change of the electrical conductivity is derived.