Material dependence of multiple-scattering effects associated with photoelectron and Auger electron diffraction along atomic chains

Multiple-scattering (MS) calculations are presented for polar intensity scans of Mg Kα excited A12s emission from linear atomic Al chains, and compared to corresponding scans of Cu LVV Auger emission from linear Cu chains. Such model calculations permit an assessment of the importance of multiple-scattering effects in substrate emission along low-index directions. Intensity reductions in forward scattering due to MS defocusing effects are seen for both Al and Cu. However, for Al they are found to be significantly slower in turning on with distance along the chain. A systematic investigation revealed that this difference between Al and Cu is caused by their different scattering potentials. This material dependence should be important in analyzing such diffraction data in a quantitative way.