Electron surface barrier structure from analysis of barrier scattering features in LEED

High resolution LEED intensity data from Cu(001), showing barrier scattering features within ∼ 3 eV from a beam threshold, have been analyzed with a two parameter “modified image barrier” (MIB) model and a three parameter “saturated image barrier” (SIB) model. It is found that a range of values of z₀, the origin of the image potential tail, in the MIB model can provide a fit of experimental maxima and minima energy locations to within 0.3 eV. With the SIB model, there is a multiplicity of values of z₀ (and corresponding value of U_s, the value of the potential with respect to the vacuum level at the jellium discontinuity), which can provide a fit to that data to 0.3 eV. Fits to within 0.05 eV were also obtained with parameters outside the values determined by previous authors. It is concluded that the validity of each model and the determination of z₀ can only be found from such experimental data if it is fitted to at least 0.05 eV.