X ray absorption spectroscopy

X-Ray Absorption Spectroscopy, X-Ray Absorption Edge Spectroscopy and Extended X-Ray Absorption Fine Structure (EXAFS) 247,280,469,980,1090,1619, 1691... 

A reevaluation of molecular structure of humic substances based on data obtained primarily from nuclear magnetic resonance spectroscopy, X-ray absorption near-edge structure spectroscopy, electrospray ionization-mass spectrometry, and pyrolysis studies was presented by Sutton and Sposito (2005). The authors consider that humic substances are collections of diverse, relatively low molecular mass components forming dynamic associations stabilized by hydrophobic interactions and hydrogen bonds. These associations are capable of organizing into micellar structures in suitable aqueous environments. Humic components display contrasting molecular motional behavior and may be spatially segregated on a scale of nanometers. Within this new structural context, these components comprise any molecules... 

X-ray techniques presently well known in catalysis include diffraction, small angle scattering, and fluorescence spectroscopy. X-ray absorption edge fine-structure spectroscopy, although known to the X-ray physicists for thirty years, is not well known in catalysis research. The promise which this field holds for catalysis has been apparent over much of the thirty year interval, but has been overshadowed by difficulties both experimental and theoretical. 

It must be kept in mind that nonelectrochemical techniques are also very useful for assessing electrode materials and more specially optical spectroscopy, x-ray absorption and diffusion, electron microscopy, calorimetry, and quartz crystal microbalance (see, for example, Ref. [6] for a quick insight about these techniques). They are used as a complement to the electrochemical ones. 

XANES X-ray absorption near-edge spectroscopy X-ray absorption near-edge structure... 

Particle diameter Inductively coupled plasma-optical emission spectrometry (ICP-OES) Fourier transform infrared spectrometry Mass spectrometry X-ray fluorescence Extended X-ray absorption fine structure (EXAFS) spectroscopy X-ray absorption near edge (XANES) spectroscopy Static and dynamic laser light scattering Scanning probe technologies... 

The radioactive nature of the actinides, especially the transuranics, can introduce significant challenges in the characterization of their complexes. In order to prevent contamination, multiple layers of containment are often required, which can limit the types of studies that can be undertaken. However, a suite of spectroscopic tools has been used to study the chemistry and speciation of the actinides. A partial list of these techniques includes absorption, emission and vibrational spectroscopies, X-ray absorption and diffraction, and multinuclear magnetic resonance. 

Introduction EPR spectroscopy Infrared spectroscopy Raman spectroscopy UV-Visible spectroscopy X-ray absorption spectroscopy Mass spectrometry of zeolites References... 

X-RAY ABSORPTION SPECTROSCOPY X-ray absorption spectroscopy (XAS) includes x-ray absorption near-edge (XANES) and extended x-ray absorption fine structure (EXAFS) spectroscopy. An advantage of XAS spectroscopy is that adsorption experiments can be carried out in aqueous systems (Fendorf et al., 1994). X-ray absorption spectroscopy has been used to examine the sorption of both cations and anions to oxide and silicate minerals found in soils, with an emphasis on ions that are potential contaminants in the environment. 

Since 1980, newer physical techniques such as Mdssbauer spectroscopy, X-ray absorption spectroscopy and iron-sulfur-core extrusion have been used to address the question of the structure of FeS-X. The initial Mossbauer spectroscopic study by (EH) Evans, Rush, Johnson and (MC W) Evans2o indicated... 

Framework and Surfaces Since compositions and structures are very diverse, surface and framework properties are also extremely varied. In terms of compositions, coordination, and chemical environments, several methods are particularly informative for the characterization of nanoporous solids, such as nuclear magnetic resonance methods (NMR), UV-visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, x-ray absorption spectroscopies, x-ray photoelectron emission spectroscopy (XPS), and electron paramagnetic resonance (EPR) (4, 6). Among them, sohd state NMR techniques arc largely employed and will be briefly described in the following. 

Inductively Coupled Plasma. Mass Spectrometry Archaeological Applications. Microscopy Techniques Scanning Electron Microscopy. Surface Analysis X-Ray Photoelectron Spectroscopy Particle-Induced X-Ray Emission Auger Electron Spectroscopy. X-Ray Absorption and Diffraction X-Ray Diffraction - Powder. X-Ray Fluorescence and Emission X-Ray Fluorescence Theory. 

Among the techniques that probe the average or long-range structure, powder X-ray diffraction (PXRD) and neutron diffraction (ND) will be briefly discussed. Techniques that provide local, atomistic information that will be mentioned are nuclear magnetic resonance (NMR) spectroscopy. X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and pair distribution function (PDF) analysis. A brief introduction to the underlying theory of each technique will be provided along with relevant examples to illustrate the type of information that can be... 

Infrared spectroscopy (IR) Raman spectroscopy X-ray absorption spectrometry (XANES, EXAFS) Nuclear magnetic resonance (NMR) Inelastic neutron scattering (INS)... 

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