- X-ray absorption spectroscopy
X-ray absorption spectroscopyis currently a widely used technique giving information on the local structure and on the electronic states in gas-phase, molecular and condensed matter.
X-ray absorption spectra are obtained by tuning the
photonenergy in a range where bound electrons can be excited(0.1-100 keV photon energy). This technique is usually applied at synchrotron radiationfacilities providing intenseand tunable x-ray beams.
Different acronyms are currently used in the literature depending on the particular applications therefore more detailson methods, technique, and significance can be found searching
XAFS(X-ray Absorption Fine Structure) or EXAFS(Extended XAFS).
The spectral region near a core excitation (near-edge region) is usually called
XANES(x-ray absorption near-edge structures)or NEXAFS(Near-Edge X-ray Absorption Fine Structure).
XASis an experimental technique used in different scientific fields including molecularand condensed matter physics, material science, chemistry, earth science, biology, and more. In particular, its unique sensitivity to the local structure, as compared to x-ray diffraction, have been exploited forstudying:
glass, amorphousand liquidsystems
* solid solutions
* Doping and
ionic implantationmaterials for electronics
* local distortions of crystal lattices
* organometallics compounds
* metal clusters
* vibrational dynamics
An informative account about the history of XAS and EXAFS (originally called Kossel's structures) is given in the paper "A History of the X-ray Absorption Fine Structure} by R. Stumm von Bordwehr", Ann. Phys. Fr. vol. 14, 377-466 (1989) (author's name is C. Brouder).
* [http://www.i-x-s.org/ International XAFS Society, official organization promoting XAS]
* [http://leonardo.phys.washington.edu/feff/ FEFF Project, University of Washington, Seattle]
* [http://gnxas.unicam.it GNXAS project and XAS laboratory, Università di Camerino]
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