EXAFS (Extended X-Ray Absorption Fine Structure) is an element specific electron scattering technique in which a core electron ejected by an x-ray photon probes the local environment of the absorbing atom. The ejected photoelectron is backscattered by the neighboring atoms around the absorbing atom and interferes constructively or destructively with the outgoing electron wave, depending on the energy of the photoelectron. The energy of the photoelectron is equal to the difference between the x-ray photon energy and a threshold energy associated with ejection of the electron. In the EXAFS experiment the photoelectron energy is varied by varying the energy of the incident x-ray beam. The interference between outgoing and backscattered electron waves has the effect of modulating the x-ray absorption coefficient so that absorption spectra determined experimentally exhibit oscillations in the absorption coefficient on the high energy sides of absorption edges.
KeywordsMetal Cluster Pure Silica Coordination Shell Average Cluster Size EXAFS Data
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