ELECTRON-ENERGY-LOSS NEAR SUPPORTED PARTICLES

A general expression for the energy-loss probability in scanning trans mission electron microscopy valid for complex microstructures is prese nted in the framework of classical dielectric theory. Calculations are carried out for small particles half embedded in a planar interface. We used experimental data for the dielectric functions that characteri ze the media and we take into account the coupling among different mul tipolar terms. Resonances, present neither in the planar-interface nor in the isolated-sphere energy-loss spectra, are found. The results ag ree with many experimental results reported in the literature of the l ast few years. A different behavior between conducting and insulator s upports is found. The effect of an oxide coating around the spherical particle is also discussed.