Photoelectron forward-scattering attenuation from the Cu(001) surface

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. © 1993 The American Physical Society.