X-ray absorption spectroscopy

X-ray absorption spectroscopy

The X-ray absorption spectroscopy is 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 photon energy in a range where bound electrons can be excited(0.1-100 keV photon energy). This technique is usually applied at synchrotron radiation facilities 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).


XAS is an experimental technique used in different scientific fields including molecular and 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, amorphous and liquid systems
* solid solutions
* Doping and ionic implantation materials for electronics
* local distortions of crystal lattices
* organometallics compounds
* metalloproteins
* metal clusters
* catalysis
* vibrational dynamics
* ions in solutions
* speciation of elements


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).

Relevant Websites

* [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]

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Absorption spectroscopy — An overview of electromagnetic radiation absorption. This example discusses the general principle using visible light as a specific example. A white beam source – emitting light of multiple wavelengths – is focused on a sample (the complementary… …   Wikipedia

  • X-ray absorption fine structure — (XAFS) is a specific structure observed in X ray absorption spectroscopy (XAS). By analyzing the XAFS, information can be acquired on the local structure and on the unoccupied electronic states.The X ray absorption spectra show a steep rise at… …   Wikipedia

  • Extended X-Ray Absorption Fine Structure — (EXAFS), or more simply X ray Absorption Spectroscopy (XAS), is an experimental method in physics and chemistry of determining the bonding of solids by analyzing oscillations in x ray absorption versus photon energy that are caused by… …   Wikipedia

  • Near edge X-ray absorption fine structure — NEXAFS (Near Edge X ray Absorption Fine Structure) is an element specific electron spectroscopic technique which is highly sensitive to bond angles, bond lengths and the presence of adsorbates. It is widely used in surface science and has also… …   Wikipedia

  • extended x-ray absorption fine structure spectroscopy — abbr. EXAFS Extended x ray absorption fine structure spectroscopy, a technique used to characterize detailed structures on the surfaces of catalysts and other solids …   Petroleum refining glossary

  • Absorption (electromagnetic radiation) — An overview of electromagnetic radiation absorption. This example discusses the general principle using visible light as specific example. A white beam source emitting light of multiple wavelengths is focused on a sample (the complementary color… …   Wikipedia

  • Absorption spectrum — A material s absorption spectrum shows the fraction of incident electromagnetic radiation absorbed by the material over a range of frequencies. An absorption spectrum is, in a sense, the opposite of an emission spectrum.Every chemical element has …   Wikipedia

  • spectroscopy — spectroscopist /spek tros keuh pist/, n. /spek tros keuh pee, spek treuh skoh pee/, n. the science that deals with the use of the spectroscope and with spectrum analysis. [1865 70; SPECTRO + SCOPY] * * * Branch of analysis devoted to identifying… …   Universalium

  • Spectroscopy — Analysis of white light by dispersing it with a prism is example of spectroscopy. Spectroscopy ( …   Wikipedia

  • X-ray spectroscopy — is a gathering name for several spectroscopic techniques for determining the electronic structure of materials by using x ray excitation. X ray emission spectroscopy Karl Manne Georg Siegbahn from Uppsala, Sweden (Nobel Prize 1924), who… …   Wikipedia