Surface core-level spectroscopy of Cu(100) and Al(100)

We present experimental and theoretical results for the surface core-level binding-energy shifts of Al(100), representative of an sp metal, and Cu(100), representative of a transition metal. Our analysis of these results leads to a unified interpretation for the different behavior of sp and transition metals. The d-electron contribution to smaller surface core-level binding energies is elucidated. © 1991 The American Physical Society.