Comparison of Model Calculations of Low-Energy-Electron-Diffraction Intensities from Be(0001) and Al(001)

Low-energy-electron-diffraction (LEED) intensity profiles are calculated using the phenomenological $s$-wave inelastic-collision model for electrons incident on Be(0001) and Al(001). The predicted intensity profiles are compared both with those obtained in two recent calculations (performed using "realistic" potentials) and with experimental data. When strong inelastic-collision damping is included in the model, the correspondence between the two types of calculations is comparable to that between either of the calculations and the experimental data. This result remains valid over wide ranges of values of the parameters used in the inelastic-collision model. It reflects an insensitivity of certain qualitative features of the model predictions to the values of the "material" parameters used in the calculation. This insensitivity is fortunate because an examination of the realistic potential models suggests that they fail to consider several surface and many-body phenomena which seem to be of significance in determining the intensity profiles.