Diffraction of UV Excited Photoelectrons by an Ordered Overlayer

Abstract
Angle resolved UV photoemission spectra obtained from Cu(111)-(√3 × √3)R30° Xe and Cu(111)-(√3 × √3)R30° CO samples are compared with spectra obtained from the clean substrate. Interest is focussed on the adsorbate induced changes in the Cu3d band range of initial energies. From the similarity between the spectra observed for the ordered Xe and CO overlayers we conclude that the changes are primarily due to diffraction of the photoexcited Cu3d electrons by the adsorbate. This is supported also by calculated photoelectron energy distributions.