Photoelectron angular distribution patterns from a single-crystal Cu(001) surface have produced dips, or ‘‘silhouettes,’’ in the low-energy, electron angular distribution measured around normal emission—a forward-scattering geometry that at higher energy produces a peak, or enhancement, in electron intensity. We have measured isoenergetic l=1 and l=2,0 photoelectrons that give different angular distribution patterns. These differences, and the low-energy electron intensity attenuation, are consistent with an electron scattering model that relies on the orbital angular momentum final-state dependence of the diffracting electron.

• Received 9 December 1992

DOI:https://doi.org/10.1103/PhysRevB.47.6851