Electronic structure and local atomic configurations of flat and stepped (111) surfaces of Ni and Cu

Results of self-consistent linear-combination-of-atomic-orbitals calculations for ideal and stepped (111) surfaces of Ni and Cu are presented. They are related to catalytic activity by a simple physical picture. The $d$ band is decomposed into a "local" $d$ band at each site. The width, position, and occupancy of this local $d$ band show simple trends as a function of site coordination. For Ni (and similarly, for Pt) sites of highest coordination tend to be the most active sites on a surface, provided they are accessible to adsorbate molecules. Copper shows little activity, regardless of site coordination.