Extended x-ray absorption fine structure EXAFS spectra

Resonance Raman spectra Cluster symmetry, ligand types, and oxidation states Extended X-ray absorption fine structure (EXAFS) spectra Metal ligand distances number and types of liganded atom... 

X-ray absorption fine structure (XAFS) spectroscopy An X-ray absorption spectroscopy (XAS) method. XAFS provides information on the physical and chemical properties of matter on an atomic scale. XAFS may include X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra. 

X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) Spectra of Pt—Sn—Alumina Catalysts... 

The transmission extended x-ray absorption fine structure (EXAFS) spectra were collected on the A-2, C-1, and C-2 stations of the Cornell High Energy Synchrotron Source (CHESS). Data reduction followed a standard procedure of pre-edge and post-edge background removal, extraction of the EXAFS oscillations taking the Fourler-transform of and finally applying an inverse transform... 

Sparks CJ Jr (1980) X-ray fluorescence microprobe for chemical analysis. In Winick H, Doniach S (eds) Synchrotron Radiation Research, Plenum Press, New York, p 459-512 Spngberg D, Hermansson K, Lindqvist-Reis P, Jalilehvand F, Sandstroem M, Persson I (2000) Model extended X-ray absorption fine structure (EXAFS) spectra from molecular dynamics data for Ca2+ and Al3+ aqueous solutions. J Phys Chem 104 10467-10472 Sposito G. (1986) Distinguishing adsorption from surface precipitation. In Geochemical Processes at Mineral Surfaces, Davis JA, Hayes KF (eds) ACS Symposium Series 323, The American Chemical Society, Washington, DC, p 217-228... 

Additional information about the structure of complex 5 was obtained from extended X-ray absorption fine structure (EXAFS) spectra. " The curve of radial distribution of atoms, RDA, which was calculated on the basis of the EXAFS spectrum of complex 5 contained only two maxima - 2.1 +0.1 A for the Pd-light atom distance and 2.6 + 0.1 A for the Pd-Pd distance. Maxima corresponding to the distances between the more remote Pd atoms were not detected. 

These conclusions from the infrared reflectance spectra recorded with Pt and Pt-Ru bulk alloys were confirmed in electrocatalysis studies on small bimetallic particles dispersed on high surface area carbon powders.Concerning the structure of bimetallic Pt-Ru particles, in situ Extended X-Ray Absorption Fine Structure (EXAFS>XANES experiments showed that the particle is a true alloy. For practical application, it is very important to determine the optimum composition of the R-Ru alloys. Even if there are still some discrepancies, several recent studies have concluded that an optimum composition about 15 to 20 at.% in ruthenium gives the best results for the oxidation of methanol. This composition is different from that for the oxidation of dissolved CO (about 50 at.% Ru), confirming a different spatial distribution of the adsorbed species. 

Intermediates were also observed in the synthesis of a neutral cluster, Ir4(CO)i2, from Ir(CO)2(acac) in the cages of zeohte NaY these were characterized by IR and extended X-ray absorption fine structure (EXAFS) spectroscopies, the latter being a technique ideally suited to investigation of small, highly dispersed species present in small amoimts in sohds. The spectra indicated dimeric intermediates, possibly Ir2(CO)8 [ 16], when the reaction was carried out in the near absence of water in the zeohte in contrast, the reaction in the dehydrated zeolite was faster, and no evidence of intermediates was observed [16]. 

Inner electrons are usually excited by X-rays. Atoms give characteristic X-ray absorption and emission spectra, due to a variety of ionization and possible inter-shell transitions. Two relevant refined X-ray absorption techniques, that use synchrotron radiation, are the so-called Absorption Edge Fine Structure (AEFS) and Extended X-ray Absorption Fine Structure (EXAFS). These techniques are very useful in the investigation of local structures in solids. On the other hand, X-Ray Fluorescence (XRF) is an important analytical technique. 

XANES) is limited to the first 30 to 40 eV past the absorption edge, whereas the extended x-ray absorption fine structure (EXAFS) covers the photon energy range from about 40 eV to about 1000 eV past the edge. This division is indeed justified, as the research community observes that the interpretation of XANES spectra is different and substantially more comphcated than that of EXAES spectra (11). 

Often the nature, number, and distances of atoms in the coordination sphere of a metal can be obtained by a relatively new method called extended X-ray absorption fine structure (EXAfS). It elaborates upon the long-known fact that X-ray absorption spectra show element-specific edges" that correspond to quantum jumps of core... 

Study by X-ray absorption spectroscopy of the extended X-ray absorption fine structure (EXAFS) has provided estimates of both the nature and the number of the nearest neighboring atoms around the Mo. The EXAFS spectra of xanthine dehydrogenase and of nitrate reductase from Chlorella confirmed the... 

In extended X-ray absorption fine structure (EXAFS) studies of urease, Hasnain, Piggott, and co-workers (33, 34) demonstrated that spectra were similar to those of benzimidazole complexes, consistent... 

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)). 

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