Distance of the Image Plane from Metal Surfaces.

The data base 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 the image plane and its trends from surface to surface and metal to metal. The model combines a nearly-free-electron representation of the crystal with Jones-Jennings-Jepsen ansatz for the saturated image barrier. The projected bulk-band gaps are taken from published determinations. Constraints are placed on the surface barrier parameters by appeals to the results of the self-consistent first-principles slab calculations. The general trend observed is for the image plane distance z sub o to decrease in the sequence (111) to (001) to (110), in the same sense as z sub j the position position of the jellium edge.