Chemisorption on transition-metal surfaces: Electronic structure

Abstract

A simple phenomenological model is used to develop a formalism for chemisorption on transition-metal surfaces. The model includes the Coulomb correlation on both the substrate atoms and the adatom. Nonorthogonality of the metal and adatom wave functions is allowed for through overlap integrals. The analysis provides condition for the existence of local moment on the adatom and can thus distinguish between the applicability of the existing molecular-orbital and Heitler-London approaches. In view of the growing wealth of reliable photoemission data, emphasis is laid on the electronic structure of the chemisorbed atom and substrate, rather than the binding energy. Though a detailed analysis of the data at the moment is hindered due to the unavailability of surface density of states of the clean substrate, simple use of the experimental value of the center of the occupied narrow d band leads to self-consistent values of various parameters. This reflects on the importance of the substrate correlation effects in chemisorbtion on narrow-band-metal surfaces. © 1973 The American Physical Society.