18.104.22.168.2 Comparative studies of image states and surface states
This chapter discusses comparative studies of image states and surface states of metals. In the following, several studies are referenced in which surface- and image-state energy, band dispersion, etc. are compared for a number of metals. Structure plots and peak intensities for surface-state emissions for different Cu, Ag, and Au surfaces are illustrated. Database of surface-state energies on the metals Cu, Ag, Au, Ni, Pd, and Pt is assembled and, with the aid of a simple model, is used to estimate the distance of an image plane and its trends from surface to surface and metal to metal. The model combines a nearly-free-electron representation of a crystal with a Jones-Jennings-Jepsen ansatz for the saturated image barrier. This chapter illustrates i) final-state energies for Ni, Cu, and Ag, ii) dependence of surface state energies on image plane distance for low index Cu surface, iii) comparison between Cu, Ag, and Au, and Ni, Pd, and Pt for the dependence of surface-state energies on image-plane distance, iv) comparison of binding energies of image-potential states determined by inverse photoemission and two-photon photoemission, v) positions of bulk band gaps and image-potential surface states (IS) for the measured Cu, Au, and Ag surfaces, and vi) energy level diagram for Cu, Ag, and Ni. Primary database of surface-state energies, comparison of the binding energies for the five surfaces of Cu(111), Ag(111), Ni(111), Cu(100) and Ag(100), and binding energy and effective mass of IS are tabulated.