Interpretation of valence loss spectra from composite media

摘要: We discuss the interpretation of valence EELS data from composite media containing defects, clusters or precipates which may be difficult to resolve individually because their small size overlap effects. In some cases a well-defined collective loss (plasmon) peak is observed position shifts slightly with changing defect concentration. other discussed here most noticeable effect appearance new peaks in spectrum can identified interface as well bulk excitations. Effective medium theories, although widely used interpret optical absorption such samples, are only partially successful explaining energy spectra and do not account for minority phase. A simple dielectric excitation model where an appropriate average made over trajectories classical particle appears offer much better explanation could useful way characterising fine-scale structure samples. The connection between this trajectory approach effective theory discussed.