EXAFS fine structure spectroscopy

EXAFS Extended X-ray absorption fine structure spectroscopy. A spectroscopic technique which can determine interatomic distances very precisely. 

Single-crystal X-ray determination, elemental analysis, and mass-spectroscopy are used for the characterisation of complexes and products. Cyclic voltammetry, EXAFS (Extended X-ray Absorption Fine Structure Spectroscopy), NMR, UV-vis spectroscopy, and IR can also be used to determine electronic properties of the ligands and their complexes [7],... 

Bulk processes can also be probed by an appropriate photon spectroscopy. For example, EXAFS provides an excellent spatial resolution with respect to the atomic surroundings. The information from Extended X-ray Absorption Fine Structure spectroscopy is contained in the oscillations of the X-ray absorption coefficient near an absorption edge e.g., the K- or L-edge). 

Extended x-ray fine structure spectroscopy (EXAFS, Synchrotron) (Bowron et al., 1998)... 

Extended X-ray absorption fine structure (EXAFS) spectrum Part of an X-ray absorption spectrum that is used to identify the coordination of atoms, estimate bond lengths, and determine the adsorption complexes on the surfaces of adsorbents. EXAFS spectra may provide useful information on the speciation (valence state), surface complexes, and the coordination of arsenic on adsorbents (e.g. (Randall, Sherman and Ragnarsdottir, 2001 Ladeira, et al. (2001) Teixeira and Ciminelli (2005) Kober, et al. (2005)) (compare with X-ray absorption spectroscopy (XAS), X-ray absorption near edge structure (XANES) spectra, and X-ray absorption fine structure spectroscopy (XAFS)). 

XRF = X-ray fluorescence spectroscopy, XPS = X-ray photoelectron spectroscopy, AES = Auger electron spectroscopy, XANES = X-ray absorption near edge spectroscopy, RAIR = Reflectance-absorbance infrared spectroscopy, EXAFS = X-ray absorption fine-structure spectroscopy, ECR = Electric contact resistance, NMR = Nuclear magnetic resonance spectroscopy, IPS = Imaging photoelectron spectromicroscopy. 

This mechanism is in agreement with the mechanism proposed by others (Belin et al., 1989 and 1995 Martin et al., 1986a, Willermet et al., 1992) using extended X-ray absorption fine structure spectroscopy (EXAFS) and infrared spectroscopy. When ZDDP is present in the lubricant formulation, the radial distribution function (RDF) indicates that crystalline iron oxide diffuses into the polyphosphate network material. 

During these temperature and gas treatments, processes like reduction, oxidation and sintering take place. In Chapter 2 it is clarified what processes are responsible for the final metal particle size and particle size distribution. This is done using a combination time resolved extended X-ray absorption fine structure spectroscopy (quick EXAFS) and mass spectrometry. 

Although they may be part of a catalyst testing [1-3] programme, investigations focused on revealing the reaction mechanism, such as in-situ Fourier transform infrared (FTIR) in transmission or reflection mode, nuclear magnetic resonance (NMR), X-ray diffraction (XRD), X-ray absorption fine-structure spectroscopy (EXAFS), X-ray photoelectron spectroscopy (XPS), electron microscopy (EM), electron spin resonance (ESR), and UV-visible (UV-vis) and the reaction cells used are not included. For the correct interpretation of the results, however, this chapter may also provide a worthwhile guide. 

EXAFS Extended X-ray absorption fine structure spectroscopy... 

The absorption edges in Fig. 10.10 are not perfectly sharp, but have a delicate fine structure ("Kossel35 lines") that was first explored in the 1930s. Since about 1970, this fine structure is now used in EXAFS (extended X-ray absorption edge fine structure spectroscopy) and in XANES (X-ray absorption near edge spectroscopy) the oscillations are due, again, to a chemical shift, which can be used to identify the local chemical environment of the emitting element in the sample. 

NEXAFS — Near-edge extended X-ray absorption fine structure (spectroscopy), evaluation of the X-ray absorption spectrum around and slightly below the absorption edge, for details see - EXAFS. 

EXAFS. Au(CH3)2(acac)/MgO. X-ray absorption fine structure spectroscopy (EXAFS) was used to study the local structure of MgO-supported gold samples prepared by decorating the MgO with Au(CH3)2(acac). These studies were completed for the sample without any post-synthesis treatment ( initial structure ) and for samples developed upon heating this sample in either He or H2 atmospheres. 

Surface analytical techniques. A variety of spectroscopic methods have been used to characterize the nature of adsorbed species at the solid-water interface in natural and experimental systems (Brown et al, 1999). Surface spectroscopy techniques such as extended X-ray absorption fine structure spectroscopy (EXAFS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) have been used to characterize complexes of fission products, thorium, uranium, plutonium, and uranium sorbed onto silicates, goethite, clays, and microbes (Chisholm-Brause et al, 1992, 1994 Dent et al, 1992 Combes et al, 1992 Bargar et al, 2000 Brown and Sturchio, 2002). A recent overview of the theory and applications of synchrotron radiation to the analysis of the surfaces of soils, amorphous materials, rocks, and organic matter in low-temperature geochemistry and environmental science can be found in Fenter et al (2002). 

TPR, Temperature-programmed reaction XPS, X-ray photoelectron spectroscopy IR, infrared spectroscopy H NMR, proton nuclear magnetic resonance spectroscopy UV-vis, ultraviolet-visible spectroscopy ESR, electron spin resonance spectroscopy TPD, temperature-programmed desorption EXAFS, extended X-ray absorption fine structure spectroscopy Raman, Raman spectroscopy C NMR, carbon-13 nuclear magnetic spectroscopy. 

Chemical vapor deposition (CVD) has been used to prepare nanoparticle catalysts, although the technology is quite expensive. Dimethylgold acetylacetonate absorbs on supports such as MgO. Decomposition at > 100°C produces an efficient CO oxidation catalyst. X-ray absorption near edge (XANES) and extended X-ray absorption fine structure spectroscopies (EXAFS) showed that, under steady-state CO oxidation conditions, the catalyst contained Au(0) in the form of (on average) Aus clusters and also additional gold as... 

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