Ultraviolet photoemission for intrinsic surface states of the noble metals

The authors have measured the photoelectron distribution curves of single-crystal faces of copper, silver and gold using photon energies of 11.83, 16.85 and 21.22 eV. The photoelectrons are collected in a narrow cone normal to the surfaces. The results show the existence of occupied surface states in the L gaps of each noble metal. The intensity of the measured surface-state peaks drastically decreases with increasing photon energy.