CHARACTERISTIC ENERGY LOSS IN REFLECTIONS OF SLOW ELECTRONS ON SODIUM SURFACES

The energy distribution of electrons reflected from freshly evaporated sodium on polycrystalline platinum surface is investigated with the retarding field method. The energy of the normally incident primary electrons is varied between 5 eV and 25 eV. A characteristic energy loss is found at 3 eV for thick films. The thickness dependence of the energy loss for thin films is found to be that of Ritchie's surface plasmon. Its excitation probability as a function of primary energy is in agreement with the theoretically predicted behaviour. © 1969.