CONSEQUENCES OF A FINITE-ENERGY RESOLUTION FOR PHOTOELECTRON DIFFRACTION SPECTRA

A broadening of energy-scan photoelectron diffraction spectra with a Gaussian or Lorentzian energy distribution, as occurs naturally in the experiment, is equivalent to the inclusion of additional damping factors in the theoretical expression for the intensity. These terms systematically suppress intensity contributions from long scattering pathways. It is therefore much easier to achieve convergence in the scattering pathway expansion by including the finite energy resolution in the calculation scheme from the beginning. In such calculations the width of the energy distribution can be used as a control parameter to optimize the computational effort depending on the extent of the fine structure required in the theoretical spectra.