Techniques for very low energy electron diffraction

LEED intensity curves between 0–50 eV contain sharp peaks due to electronic surface resonances. Successful comparison with theory requires an accurate knowledge of the incidence angles and energy resolution ≲0.15 eV. It is shown that these requirements can be achieved with a conventional LEED system. The resolution was obtained by doubly modulating the four grid retarding optics and the electron gun. The incidence angles were found with a simple photographic technique.