Core- and valence-band energy-level shifts in small two-dimensional islands of gold deposited on Pt(100): The effect of step-edge, surface, and bulk atoms

Photoemission techniques were used to study the electronic properties of two-dimensional islands of Au deposited on Pt(100) in the submonolayer range. Shifts of approximately 0.6 eV were observed in both valence-band and core-level binding energies from $\ensuremath{\Theta}=1 \mathrm{to} 0.1$. These shifts are interpreted in terms of the increasing proportion of island edges as the gold coverage approaches zero. Above $\ensuremath{\Theta}=1$ the surface-bulk energy shift was found to agree with previously published data.