Abstract
Analysis of the core-level and valence-band binding-energy shifts at the Cu(100) surface demonstrates that holes in the Cu 3d band are screened by 4sp electrons as effectively as are deep core holes. The common view of the photoemission final state as simply an itinerant 3d hole should be replaced by the concept of a 3d hole and its 4sp screening charge propagating through the lattice together. It appears that this phenomenon also plays an important role in determining photoemission properties of transition metals.