X-ray Absorption Spectroscopy (XAS) notes in University of Waterloo in 2007
The X-ray Absorption spectroscopy is a powerful probe to explore the local environment around an atom, that is, its local structure whatever the type of compound that can be studied (gas, liquid, molecule, crystallized or disordered solid...). Moreover, as this technique is sensitive to a given nature of atom, it can help to study the structure of a single doping element. This technique requires high flux of tunable monochromatic X-ray, which explains why it has been mainly developed in practical use since the synchrotron centerswere made available. Since then, the technique has been broadely used in many fields ranging from catalysis, energy (materials for batteries), geology (pollutants speciation), biology, pharmacology... the specificity of this technique is that X-rays are used to create in the matter, photoelectrons that are the actual probes. From this mechanism, two main aspects can be described: EXAFS (Extented-X-ray Absorption Fine Structure) that provides information about the surrounding environment around the atom that ejected this photoelectron
XANES (X-ray Absorption Near Edge Structure) that provides an information on the xidation Degree and local site of the atom.
This lecture is a practical course that will provide theoretical background required to understand this mechanism and practical skills that will allow the students to analyze by themselves XAS spectra and to extract the useful information.
This cours does not require any specific background in physics or chemistry.
We will describe:
- the bases of physics (X-ray-matter interaction) involved in this technique
- the description of a synchrotron ring and related techniques
- the description of a XAS beamline
- the general theory of XAS and its specificity in the EXAFS equation
- the steps and parameters of practical analysis
- the stereochemical informations that can be extracted from the study of the
absorption edge
This course will be supported by tutorials/lab works devoted to actual analysis
of EXAFS spectra on microcomputers.[attach]4602[/attach][attach]4601[/attach] Thank you ! thank you :victory:
Supplementary Slides about X-ray Absorption Spectroscopy (XAS) in University of Waterloo
More Slides can be downloaded from Box.net[url]http://www.box.net/shared/vl2un2fffn[/url]
Have fun! appreciate
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