| Abstract: | We present a model calculation, based on the Falicov-Kimball model for metal-insulator transitions, which shows that for a mixed-valence solid with a surface, the average valence of the atoms at the surface may be substantially different from that in the bulk. The effect, which we have calculated only for T = 0 and neglecting hybridization, is due to the different local density of itinerant states at the surface and bulk atoms. Surface states contribute to the valence difference but are not solely responsible for it. |
