ANGULAR-DISTRIBUTIONS OF AUGER ELECTRONS FROM SURFACES - CONCLUSIONS FROM FULL MULTIPLE-SCATTERING SIMULATIONS

We address some of the recent controversies regarding the interpretation of Auger electron diffraction patterns by simulating those from the 64 eV M2,3VV and the 914 eV L3VV lines from a Cu(001) surface. The lower-energy diffraction pattern, in particular, is found to be strongly dependent on the angular momentum l of the emitted Auger electrons, in line with the observations of some other authors. However, we find that both peaks and dips are observed on the same diffraction pattern at the projections of different atomic rows, indicating that the angular momentum of the source wave cannot be the only determinant of these features. We find that the distance of the scatterer from the source, as well as overlap and interference effects from scatterers in other atomic rows to be an equally important determining factor. On comparing our simulations with experimental diffraction patterns, we find that, for an l = 3 source wave, our simulations agree remarkably well with the data from both Auger lines.