Everything Else in the Spectrum
The energy resolution of the magnetic prism spectrometer is very good, which means that the energy-loss spectrum contains a wealth of information about the specimen in addition to its basic elemental chemistry. In the previous chapter, we mentioned how we can learn about chemistry using ionization edges. Much of this chemical information is contained in fine-detail intensity variations at the ionization edges in the core-loss spectra termed energy-loss near-edge structure (ELNES) and extended energy-loss fine structure (EXELFS). From this fine structure, we can obtain information on how the ionized atom is bonded, the coordination of the atom, and its density of states. Furthermore, we can probe the distribution of other atoms around the ionized atom, i.e., the radial distribution function (RDF). Understanding these phenomena requires that we use certain concepts from atomic and quantum physics. The nonphysicist can skip some sections at this time and just concentrate on the results. The rewards of working through this topic will be an appreciation of some of the more powerful aspects of EELS.
KeywordsRadial Distribution Function Interband Transition Plasmon Peak Ionization Edge Unfilled State
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