scholarly journals Experimental and ab initio investigations of the x-ray absorption near edge structure of orthorhombic LuMnO3

2012 ◽  
Vol 100 (25) ◽  
pp. 252901 ◽  
Author(s):  
Y. Hu ◽  
C. N. Borca ◽  
E. Kleymenov ◽  
M. Nachtegaal ◽  
B. Delley ◽  
...  
Keyword(s):  
Ab Initio ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

scholarly journals Solving local structure around dopants in metal nanoparticles with ab initio modeling of X-ray absorption near edge structure

2016 ◽  
Vol 18 (29) ◽  
pp. 19621-19630 ◽  
Author(s):  
Janis Timoshenko ◽  
Atal Shivhare ◽  
Robert W. J. Scott ◽  
Deyu Lu ◽  
Anatoly I. Frenkel
Keyword(s):  
Ab Initio ◽  
Metal Nanoparticles ◽  
Local Structure ◽  
Heterogeneous Catalysts ◽  
Edge Structure ◽  
X Ray ◽  
Metal Impurities ◽  
Local Environments ◽  
X Ray Absorption ◽  
Xanes Analysis

XANES analysis guided by ab initio modeling is proposed for refinement of local environments around metal impurities in heterogeneous catalysts.

New developments in the theory and interpretation of X-ray spectra based on fast parallel calculations

2002 ◽  
Vol 10 (1) ◽  
pp. 43-45 ◽  
Author(s):  
J. J. Rehr ◽  
A. L. Ankudinov
Keyword(s):  
Ab Initio ◽  
Structural Biology ◽  
Significant Progress ◽  
Edge Structure ◽  
New Developments ◽  
X Ray ◽  
The Past ◽  
Current State ◽  
X Ray Absorption ◽  
Made In

There has been dramatic progress over the past decade both in theory and inab initiocalculations of X-ray absorption fine structure. Significant progress has also been made in understanding X-ray absorption near-edge structure (XANES). This contribution briefly reviews the developments in this field leading up to the current state. One of the key advances has been the development of severalab initiocodes such asFEFF, which permit an interpretation of the spectra in terms of geometrical and electronic properties of a material. Despite this progress, XANES calculations have remained challenging both to compute and to interpret. However, recent advances based on parallel Lanczos multiple-scattering algorithms have led to speed increases of typically two orders of magnitude, making fast calculations practicable. Improvements in the interpretation of near-edge structure have also been made. It is suggested that these developments can be advantageous in structural biology,e.g.in post-genomics studies of metalloproteins.

Ab Initio XAFS and XANES Standards

1993 ◽  
Vol 307 ◽  
Author(s):  
J. J. Rehr ◽  
S. I. Zabinsky ◽  
R. C. Albers
Keyword(s):  
Fine Structure ◽  
Ab Initio ◽  
Multiple Scattering ◽  
State Of The Art ◽  
Experimental Measurements ◽  
Edge Structure ◽  
X Ray ◽  
Coordination Numbers ◽  
X Ray Absorption ◽  
Better Than

ABSTRACTAb initio x-ray-absorption fine structure (XAFS) and x-ray-absorption near edge structure (XANES) standards are developed for molecules and solids. These standard XAFS spectra are obtained from ab initio XAFS calculations, using an automated code, FEFF, which we have extended to include multiple-scattering (MS) and XANES calculations. Our treatment is based on state-of-the-art curved-wave MS theory. Sample results are presented and compared with experiment. We find that these theoretical standards are comparable with experimental measurements, yielding distance determinations better than 0.02 Å and coordination numbers better than 20%. Our approach also gives a new MS interpretation of the σ* shape-resonances in XANES.

Ab initio simulation of core-hole effects on the X-ray absorption near edge structure of GaP

2009 ◽  
Vol 404 (12-13) ◽  
pp. 1643-1647 ◽  
Author(s):  
Quan Li ◽  
Hongbo Wang ◽  
Yang Xia ◽  
Tian Cui ◽  
Yanming Ma ◽  
...  
Keyword(s):  
Ab Initio ◽  
Core Hole ◽  
Edge Structure ◽  
Ab Initio Simulation ◽  
X Ray ◽  
X Ray Absorption

X-ray Absorption Near-edge and Pre-edge Structure: The Contributions of ab initio Plane-wave Pseudopotential Calculations and of Multiplet Theory

2004 ◽  
Vol 10 (S02) ◽  
pp. 90-91
Author(s):  
Delphine Cabaret ◽  
Emilie Gaudry ◽  
Francesco Mauri ◽  
Marie-Anne Arrio ◽  
Christian Brouder ◽  
...  
Keyword(s):  
Plane Wave ◽  
Ab Initio ◽  
Edge Structure ◽  
X Ray ◽  
Pseudopotential Calculations ◽  
X Ray Absorption

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

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
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