Investigation of Energy Loss Spectra of Reflected Electrons

Selection Rules in Electron-Excited4d→4fTransitions at Intermediate Incident Energies

“…14 Trivalent Ce and Gd 16 show very similar effects, but with a more complex multiplet pattern, and this is consistent with earlier observations of anomalous behavior in the rare-earth systems by Borovskii and Komarov. 17 We may note that the strong primary energy dependence in the electron loss spectra described here can be satisfactorily explained within a single configurational description, and there is no need to invoke dynamical screening mechanisms of the type invoked by Kanski and Wendin 18 for 3d losses. Although the nondipole excitation effects outlined in this Letter will be less easy to isolate in systems other than the rare-earth systems, they will nevertheless be present, and for example, triplet excitation will be an important contributing factor to effects resulting from variation of the primary energy on electron losses of transition metals.…”