APPLICATION OF PSEUDOPOTENTIALS TO LOW-ENERGY ELECTRON DIFFRACTION .I. CALCULATION OF POTENTIAL AND INNER POTENTIAL

We explain how to set up a potential suitable for low-energy electron diffraction (LEED) calculations. It is found that for off-diagonal matrix elements, the exchange contribution must be calculated from the full Hartree-Fock exchange operator and not from the local Slater approximation. The potential has to be transformed into a pseudopotential to obtain good convergence in k space. Some numbers, which include the 'inner potential', are presented from calculations on nickel, niobium and graphite. Comparison with experiment shows the potentials to be accurate to within ±2 eV.