APPLICATION OF PSEUDOPOTENTIALS TO LOW-ENERGY ELECTRON DIFFRACTION .3. SIMPLIFYING EFFECT OF INELASTIC SCATTERING

The consequences of absorptive processes for low-energy electrons are discussed from a band structure point of view. By introducing sufficient absorption as an imaginary component of the potential, calculated widths of peaks in the diffraction intensities are fitted to experiment, yielding an estimate for the inelastic intensity-extinction distance of 6 at E = 70 ev in nickel. Such strong absorption, together with the nature of the elastic scattering, tends to confine flux in the crystal to a narrow cone about the incident beam, making feasible an accurate approximate scheme of calculation which constitutes a considerable simplification on present, formally exact, schemes.