Exafs Evidence For Atom Location In Icosahedral TiZrNi And Hydrogenated TiZrNi Quasicrystals

1998 ◽  
Vol 553 ◽  
Author(s):  
A. Sadoc ◽  
J. K. Kim ◽  
K.F. Kelton
Keyword(s):  
Fine Structure ◽  
Metal Atom ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Absorption Fine ◽  
Different Types ◽  
X Ray Absorption ◽  
Absorption Edges

AbstractWe present results from the first extended X-ray absorption fine-structure studies in a Ti/Zrbased quasicrystal. The icosahedral Ti53Zr27Ni20 phase and an icosahedral Ti45Zr38Ni17 phase that also contains 1.7 hydrogen atoms for each metal atom were investigated. Experiments performed above the Ti, Ni and Zr K absorption edges have allowed to identify different types of atomic subshells around the Ti, Ni and Zr atoms. Significant differences are observed between these two quasicrystalline alloys, suggesting preferential sites for the hydrogen atoms.

Extended X-Ray Absorption Fine Structure from Hydrogen Atoms in Water

2000 ◽  
Vol 85 (20) ◽  
pp. 4289-4292 ◽  
Author(s):  
Kevin R. Wilson ◽  
James G. Tobin ◽  
A. L. Ankudinov ◽  
J. J. Rehr ◽  
R. J. Saykally
Keyword(s):  
Fine Structure ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

scholarly journals X-ray Absorption Fine Structure Combined with X-ray Fluorescence Spectrometry. Improvement of Spectral Resolution at the Absorption Edges of 9−29 keV

2006 ◽  
Vol 78 (6) ◽  
pp. 2075-2075
Author(s):  
Yasuo Izumi ◽  
Hiroyasu Nagamori ◽  
Fumitaka Kiyotaki ◽  
Dilshad Masih ◽  
Taketoshi Minato ◽  
...  
Keyword(s):  
Fine Structure ◽  
Spectral Resolution ◽  
Fluorescence Spectrometry ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption ◽  
Absorption Edges

Determination of Interatomic Distances from X-Ray Absorption Fine Structure

1965 ◽  
Vol 9 ◽  
pp. 398-409 ◽  
Author(s):  
F. W. Lytle
Keyword(s):  
Fine Structure ◽  
High Energy ◽  
Quantitative Agreement ◽  
Applied Theory ◽  
Interatomic Distances ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption ◽  
Absorption Edges

AbstractA pragmatic, easily applied theory of the extended X-ray absorption fine structure found on the high-energy side of absorption edges is developed. This simple model can be successfully applied to determinations of interatomic distances, and it accounts for differences in Kronig structure on different absorption edges in the same material. Quantitative agreement with experimental data is good.

XAFS in the high-energy region

1998 ◽  
Vol 5 (3) ◽  
pp. 1007-1009 ◽  
Author(s):  
Y. Nishihata ◽  
O. Kamishima ◽  
Y. Kubozono ◽  
H. Maeda ◽  
S. Emura
Keyword(s):  
Fine Structure ◽  
Energy Region ◽  
High Energy ◽  
High Energy Region ◽  
Core Hole ◽  
X Ray ◽  
The Core ◽  
Absorption Fine ◽  
X Ray Absorption ◽  
Absorption Edges

XAFS (X-ray absorption fine-structure) spectra were measured near K-absorption edges of Ce (40.5 keV), Dy (53.8 keV), Ta (67.4 keV) and Pt (78.4 keV). The blunt K-edge jump due to the finite lifetime of the core hole was observed. This makes it difficult to extract EXAFS (extended X-ray absorption fine-structure) functions at low k values. Local structure parameters can be evaluated from the EXAFS spectra above K-absorption edges in the high-energy region as well as from those above L III-edges. It was found that the finite-lifetime effect of the core hole is effectively taken into the photoelectron mean-free-path term, as predicted theoretically.

X-ray Absorption Fine Structure Combined with X-ray Fluorescence Spectrometry. Improvement of Spectral Resolution at the Absorption Edges of 9−29 keV

2005 ◽  
Vol 77 (21) ◽  
pp. 6969-6975 ◽  
Author(s):  
Yasuo Izumi ◽  
Hiroyasu Nagamori ◽  
Fumitaka Kiyotaki ◽  
Dilshad Masih ◽  
Taketoshi Minato ◽  
...  
Keyword(s):  
Fine Structure ◽  
Spectral Resolution ◽  
Fluorescence Spectrometry ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption ◽  
Absorption Edges

Coordination of Sr and Mg in calcite and aragonite

2007 ◽  
Vol 71 (5) ◽  
pp. 539-552 ◽  
Author(s):  
A. A. Finch ◽  
N. Allison
Keyword(s):  
Fine Structure ◽  
Structural State ◽  
Bond Distance ◽  
Edge Structure ◽  
X Ray ◽  
Absorption Fine ◽  
Different Types ◽  
Temperature Dependences ◽  
X Ray Absorption ◽  
Mg Substitution

AbstractStrontium and Mg in calcite and aragonite are widely used as proxies of temperature in palaeoenvironmental reconstructions. We use X-ray absorption fine structure (XAFS) to examine Sr and Mg substitution in calcite and aragonite. We have measured the K-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) of Mg and Sr-bearing calcite and aragonite, plus the carbonates: strontianite, hydromagnesite, magnesite, dolomite and a suite of calcites with differing amounts of Mg. The Sr substitutes ideally for Ca in aragonite but causes a small (2%) dilation of the site. Strontium substitutes for octahedral Ca in calcite but with a 6.5% dilation and distortion. Magnesium in the calcites studied provides a variable XANES indicating that the Mg structural state in calcite is variable. Refinement of EXAFS gives Mg–O bond distances of ∼2.12 Å, which are much smaller than the Ca–O bond distance of 2.35 Å but consistent with published amounts of relaxation of the calcite structure. The XANES and EXAFS are consistent with a model whereby some calcites contain nanodomains, e.g. of dolomite and/or huntite structures. The variability in the XANES can be explained by domains of different types and/or sizes. Substitution of Mg into aragonite has 9-fold coordination but relatively short bond distances (2.08 Å) demonstrating either: (1) substantial distortion of the site; or (2) that Mg is accommodated in nanodomains of an unknown phase. Variability in the Mg structural state in calcite may be linked to the variety of temperature dependences observed, e.g. in foraminiferal calcite

Structure of magnetic thin films and nanostructures studied by extended X-ray absorption fine structure

2000 ◽  
Vol 454-456 ◽  
pp. 723-728 ◽  
Author(s):  
H. Magnan ◽  
P. Le Fèvre ◽  
A. Midoir ◽  
D. Chandesris ◽  
H. Jaffrès ◽  
...  
Keyword(s):  
Thin Films ◽  
Fine Structure ◽  
Magnetic Thin Films ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption
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