SECONDARY-ELECTRON AND ENERGY-LOSS SPECTRA OF COPPER

The spectra of secondary electrons from copper show structure up to a kinetic energy of 300 eV, analogous to features observed in electron energy loss spectroscopy. We report EELS and SE data, up to 300 eV, obtained for a Cu(100) surface in order to show that they both are closely related to the unoccupied DOS. Features in SE spectra originate mostly from the emission channels out of the 3d and 3p levels, and those of EELS up to the threshold of 3p excitation energy stem from the transitions out of the 3d bands. This is well-reproduced by real-space multiple-scattering calculations of unoccupied density of states for different angular momentum components. The success of the interpretation confirms that the density of states dictates the observed features.