X-ray absorption near edge structure as a source of structural information

2008 ◽  
Vol 49 (S1) ◽  
pp. 102-106 ◽  
Author(s):  
A. V. Soldatov
Keyword(s):  
Structural Information ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

scholarly journals Simultaneous two-color X-ray absorption spectroscopy using Laue crystals at an inverse-compton scattering X-ray facility

2021 ◽  
Vol 28 (6) ◽  
Author(s):  
Juanjuan Huang ◽  
Benedikt Günther ◽  
Klaus Achterhold ◽  
Martin Dierolf ◽  
Franz Pfeiffer
Keyword(s):  
Compton Scattering ◽  
Absorption Spectroscopy ◽  
Bimetallic Catalyst ◽  
Structural Information ◽  
Synergistic Effects ◽  
Edge Structure ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Inverse Compton ◽  
X Ray Absorption

X-ray absorption spectroscopy (XAS) is an element-selective technique that provides electronic and structural information of materials and reveals the essential mechanisms of the reactions involved. However, the technique is typically conducted at synchrotrons and usually only probes one element at a time. In this paper, a simultaneous two-color XAS setup at a laboratory-scale synchrotron facility is proposed based on inverse Compton scattering (ICS) at the Munich Compact Light Source (MuCLS), which is based on inverse Compton scattering (ICS). The setup utilizes two silicon crystals in a Laue geometry. A proof-of-principle experiment is presented where both silver (Ag) and palladium (Pd) K-edge X-ray absorption near-edge structure spectra were simultaneously measured. The simplicity of the setup facilitates its migration to other ICS facilities or maybe to other X-ray sources (e.g. a bending-magnet beamline). Such a setup has the potential to study reaction mechanisms and synergistic effects of chemical systems containing multiple elements of interest, such as a bimetallic catalyst system.

Extraction of local coordination structure in a low-concentration uranyl system by XANES

2016 ◽  
Vol 23 (3) ◽  
pp. 758-768 ◽  
Author(s):  
Linjuan Zhang ◽  
Jing Zhou ◽  
Jianyong Zhang ◽  
Jing Su ◽  
Shuo Zhang ◽  
...  
Keyword(s):  
Structural Information ◽  
Chemical Properties ◽  
Edge Structure ◽  
X Ray ◽  
Low Concentration ◽  
Simplified Approach ◽  
Bond Lengths ◽  
Uranyl Carbonate ◽  
X Ray Absorption ◽  
Xanes Analysis

Obtaining structural information of uranyl species at an atomic/molecular scale is a critical step to control and predict their physical and chemical properties. To obtain such information, experimental and theoreticalL3-edge X-ray absorption near-edge structure (XANES) spectra of uranium were studied systematically for uranyl complexes. It was demonstrated that the bond lengths (R) in the uranyl species and relative energy positions (ΔE) of the XANES were determined as follows: ΔE1= 168.3/R(U—Oax)2− 38.5 (for the axial plane) and ΔE2= 428.4/R(U—Oeq)2− 37.1 (for the equatorial plane). These formulae could be used to directly extract the distances between the uranium absorber and oxygen ligand atoms in the axial and equatorial planes of uranyl ions based on the UL3-edge XANES experimental data. In addition, the relative weights were estimated for each configuration derived from the water molecule and nitrate ligand based on the obtained average equatorial coordination bond lengths in a series of uranyl nitrate complexes with progressively varied nitrate concentrations. Results obtained from XANES analysis were identical to that from extended X-ray absorption fine-structure (EXAFS) analysis. XANES analysis is applicable to ubiquitous uranyl–ligand complexes, such as the uranyl–carbonate complex. Most importantly, the XANES research method could be extended to low-concentration uranyl systems, as indicated by the results of the uranyl–amidoximate complex (∼40 p.p.m. uranium). Quantitative XANES analysis, a reliable and straightforward method, provides a simplified approach applied to the structural chemistry of actinides.

X-ray absorption spectroscopy principles and practical use in materials analysis

2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Wolfgang Grünert ◽  
Konstantin Klementiev
Keyword(s):  
Fine Structure ◽  
Structural Analysis ◽  
Disordered Systems ◽  
Structural Information ◽  
Research Strategies ◽  
Edge Structure ◽  
X Ray ◽  
Absorption Fine ◽  
Wide Range ◽  
X Ray Absorption

AbstractThe X-ray Absorption Fine Structure (XAFS) with its subregions X-ray Absorption Near-edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) is a powerful tool for the structural analysis of materials, which is nowadays a standard component of research strategies in many fields. This review covers a wide range of topics related to its measurement and use: the origin of the fine structure, its analytical potential, derived from the physical basis, the environment for measuring XAFS at synchrotrons, including different measurement geometries, detection modes, and sample environments, e. g. for in-situ and operando work, the principles of data reduction, analysis, and interpretation, and a perspective on new methods for structure analysis combining X-ray absorption with X-ray emission. Examples for the application of XAFS have been selected from work with heterogeneous catalysts with the intention to demonstrate the strength of the method providing structural information about highly disperse and disordered systems, to illustrate pitfalls in the interpretation of results (e. g. by neglecting the averaged character of the information obtained) and to show how its merits can be further enhanced by combination with other methods of structural analysis and/or spectroscopy.

The contribution of XANES spectroscopy to tribology

2007 ◽  
Vol 85 (10) ◽  
pp. 816-830 ◽  
Author(s):  
M Nicholls ◽  
M N Najman ◽  
Z Zhang ◽  
M Kasrai ◽  
P R Norton ◽  
...  
Keyword(s):  
Structural Information ◽  
Film Formation ◽  
Engine Oil ◽  
Formation Mechanisms ◽  
Metallic Surfaces ◽  
Edge Structure ◽  
X Ray ◽  
Macro Scale ◽  
X Ray Absorption ◽  
Xanes Analysis

X-ray absorption near edge structure spectroscopy (XANES) analysis has been routinely used to study the complex chemical interactions between additives in engine oil and metallic surfaces during high-temperature and pressure reciprocating wear conditions. XANES analysis provides detailed chemical and structural information on the resultant antiwear and tribo films formed on metallic surfaces. The following review will illustrate how XANES analysis on the macro scale can provide the information required to elucidate complex film formation mechanisms, then describes the use of emerging XANES spectromicroscopy to such systems, and concludes by showing the complementary nature of the macro and micro scale spatially resolved XANES analysis; Professor Bancroft has utilized the combination of these to stay at the forefront of XANES research in the field of tribology and in spectroscopy science in general.Key words: tribology, XANES, X-ray absorption near edge structure spectroscopy, metals, thiophosphates, spectromicroscopy, tribochemistry.

Chemical and orientational imaging of polymeric samples

1994 ◽  
Vol 52 ◽  
pp. 68-69
Author(s):  
H. Ade ◽  
B. Hsiao ◽  
G. Mitchell ◽  
E. Rightor ◽  
A. P. Smith ◽  
...  
Keyword(s):  
Ethylene Terephthalate ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Carbonyl Groups ◽  
Aromatic Rings ◽  
Edge Structure ◽  
X Ray ◽  
Scanning Transmission ◽  
Polymeric Samples ◽  
X Ray Absorption

We have used the Scanning Transmission X-ray Microscope at beamline X1A (X1-STXM) at Brookhaven National Laboratory (BNL) to acquire high resolution, chemical and orientation sensitive images of polymeric samples as well as point spectra from 0.1 μm areas. This sensitivity is achieved by exploiting the X-ray Absorption Near Edge Structure (XANES) of the carbon K edge. One of the most illustrative example of the chemical sensitivity achievable is provided by images of a polycarbonate/pol(ethylene terephthalate) (70/30 PC/PET) blend. Contrast reversal at high overall contrast is observed between images acquired at 285.36 and 285.69 eV (Fig. 1). Contrast in these images is achieved by exploring subtle differences between resonances associated with the π bonds (sp hybridization) of the aromatic groups of each polymer. PET has a split peak associated with these aromatic groups, due to the proximity of its carbonyl groups to its aromatic rings, whereas PC has only a single peak.

Full-Field Calcium K-Edge X-ray Absorption Near-Edge Structure Spectroscopy on Cortical Bone at the Micron-Scale: Polarization Effects Reveal Mineral Orientation

2016 ◽  
Vol 88 (7) ◽  
pp. 3826-3835 ◽  
Author(s):  
Bernhard Hesse ◽  
Murielle Salome ◽  
Hiram Castillo-Michel ◽  
Marine Cotte ◽  
Barbara Fayard ◽  
...  
Keyword(s):  
Cortical Bone ◽  
Edge Structure ◽  
Full Field ◽  
Polarization Effects ◽  
X Ray ◽  
X Ray Absorption

scholarly journals Database of ab initio L-edge X-ray absorption near edge structure

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yiming Chen ◽  
Chi Chen ◽  
Chen Zheng ◽  
Shyam Dwaraknath ◽  
Matthew K. Horton ◽  
...  
Keyword(s):  
High Throughput ◽  
Scattering Theory ◽  
Research Community ◽  
Metal Compounds ◽  
Edge Structure ◽  
X Ray ◽  
Initial Release ◽  
Computational Workflow ◽  
X Ray Absorption

AbstractThe L-edge X-ray Absorption Near Edge Structure (XANES) is widely used in the characterization of transition metal compounds. Here, we report the development of a database of computed L-edge XANES using the multiple scattering theory-based FEFF9 code. The initial release of the database contains more than 140,000 L-edge spectra for more than 22,000 structures generated using a high-throughput computational workflow. The data is disseminated through the Materials Project and addresses a critical need for L-edge XANES spectra among the research community.

Theoretical and experimental investigation of point defects in cubic boron nitride

MRS Advances ◽  
2017 ◽  
Vol 2 (29) ◽  
pp. 1545-1550 ◽  
Author(s):  
Nicholas L. McDougall ◽  
Jim G. Partridge ◽  
Desmond W. M. Lau ◽  
Philipp Reineck ◽  
Brant C. Gibson ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Cubic Boron Nitride ◽  
Optical Emission ◽  
Wide Band ◽  
Wide Band Gap ◽  
Edge Structure ◽  
X Ray ◽  
Substitutional Defects ◽  
X Ray Absorption ◽  
Annealing Experiments

ABSTRACTCubic boron nitride (cBN) is a synthetic wide band gap material that has attracted attention due to its high thermal conductivity, optical transparency and optical emission. In this work, defects in cBN have been investigated using experimental and theoretical X-ray absorption near edge structure (XANES). Vacancy and O substitutional defects were considered, with O substituted at the N site (ON) to be the most energetically favorable. All defects produce unique signatures in either the B or N K-edges and can thus be identified using XANES. The calculations coupled with electron-irradiation / annealing experiments strongly suggest that ON is the dominant defect in irradiated cBN and remains after annealing. This defect is a likely source of optical emission in cBN.

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