Extended x-ray-absorption fine-structure and x-ray-absorption near-edge-structure studies of glassyNi66B33: A multishell modeling of the Ni-Ni distribution

1984 ◽  
Vol 29 (2) ◽  
pp. 651-672 ◽  
Author(s):  
Joe Wong ◽  
Howard H. Liebermann
Keyword(s):  
Fine Structure ◽  
Edge Structure ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

Extended X-ray absorption fine structure and multiple-scattering simulation of nickel dithiolene complexes Ni[S2C2(CF3)2]2n(n= −2, −1, 0) and an olefin adduct Ni[S2C2(CF3)2]2(1-hexene)

2015 ◽  
Vol 22 (1) ◽  
pp. 124-129 ◽  
Author(s):  
Weiwei Gu ◽  
Hongxin Wang ◽  
Kun Wang
Keyword(s):  
Fine Structure ◽  
Multiple Scattering ◽  
Edge Structure ◽  
X Ray ◽  
Absorption Fine ◽  
Square Planar ◽  
Square Planar Complexes ◽  
Uv Visible ◽  
Edge Features ◽  
X Ray Absorption

A series of Ni dithiolene complexes Ni[S2C2(CF3)]2n(n= −2, −1, 0) (1,2,3) and a 1-hexene adduct Ni[S2C2(CF3)2]2(C6H12) (4) have been examined by NiK-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopies. Ni XANES for1–3reveals clear pre-edge features and approximately +0.7 eV shift in the NiK-edge position for `one-electron' oxidation. EXAFS simulation shows that the Ni—S bond distances for1,2and3(2.11–2.16 Å) are within the typical values for square planar complexes and decrease by ∼0.022 Å for each `one-electron' oxidation. The changes in NiK-edge energy positions and Ni—S distances are consistent with the `non-innocent' character of the dithiolene ligand. The Ni—C interactions at ∼3.0 Å are analyzed and the multiple-scattering parameters are also determined, leading to a better simulation for the overall EXAFS spectra. The 1-hexene adduct4presents no pre-edge feature, and its NiK-edge position shifts by −0.8 eV in comparison with its starting dithiolene complex3. Consistently, EXAFS also showed that the Ni—S distances in4elongate by ∼0.046 Å in comparison with3. The evidence confirms that the neutral complex is `reduced' upon addition of olefin, presumably by olefin donating the π-electron density to the LUMO of3as suggested by UV/visible spectroscopy in the literature.

Fluorescence Extended X-Ray Absorption Fine Structure Study on Local Structures of Rare-Earth-Doped InGaGdN

2016 ◽  
Vol 1133 ◽  
pp. 429-433
Author(s):  
Siti Nooraya Mohd Tawil ◽  
Shuichi Emura ◽  
Daivasigamani Krishnamurthy ◽  
Hajime Asahi
Keyword(s):  
Fine Structure ◽  
Rare Earth ◽  
Nearest Neighbor ◽  
Structure Study ◽  
Edge Structure ◽  
X Ray ◽  
Local Structures ◽  
Absorption Fine ◽  
X Ray Absorption

Local structures around gadolinium atoms in rare-earth (RE)-doped InGaGdN thin films were studied by means of fluorescence extended X-ray absorption fine structure (EXAFS) measured at the Gd LIII-edges. The samples were doped with Gd in-situ during growth by plasma-assisted molecular beam epitaxy (PAMBE). Gd LIII-edge EXAFS signal from the GaGdN, GdN and Gd foil were also measured as reference. The X-ray absorption near edge structure (XANES) spectra around Gd LIII absorption edge of InGaGdN samples observed at room temperature indicated the enhancement of intensities with the increase of Gd composition. Further EXAFS analysis inferred that the Gd atoms in InGaN were surrounded by similar atomic shells as in the case of GaGdN with the evidence indicating majority of Gd atoms substituted into Ga sites of InGaGdN. A slight elongation of bond length for the 2nd nearest-neighbor (Gd–Ga) of sample with higher Gd concentration was also observed.

Effect of the ligand in the crystal structure of zinc oxide: an x-ray powder diffraction, x-ray absorption near-edge structure, and an extended x-ray absorption fine structure study

2016 ◽  
Vol 6 (2) ◽  
pp. 93-97
Author(s):  
María de los A. Cepeda-Pérez ◽  
Cristina M. Reyes-Marte ◽  
Valerie Ann Carrasquillo ◽  
William A. Muñiz ◽  
Edgar J. Trujillo ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Zinc Oxide ◽  
Fine Structure ◽  
Powder Diffraction ◽  
Structure Study ◽  
Edge Structure ◽  
X Ray ◽  
Absorption Fine ◽  
Image Position ◽  
X Ray Absorption

Abstract

X-Ray Absorption Fine Structure of Aged, Pu-Doped Glass and Ceramic Waste Forms

1997 ◽  
Vol 506 ◽  
Author(s):  
N.J. Hess ◽  
W.J. Weber ◽  
S.D. Conradson
Keyword(s):  
Fine Structure ◽  
Isotopic Ratio ◽  
Edge Structure ◽  
X Ray ◽  
Ceramic Waste ◽  
Absorption Fine ◽  
Waste Forms ◽  
Simulated Waste ◽  
X Ray Absorption ◽  
Accumulated Dose

ABSTRACTX-Ray Absorption Fine Structure (XAFS) spectroscopic studies were performed on a suite of compositionally identical Pu-doped simulated waste glasses prepared 15 years ago at different aactivities by varying the 239Pu/f238 Pu isotopic ratio. The resulting α-activities range from 1.9 × 107 to 4.2 × 109 Bq/g. These samples have a current, accumulated dose that ranges from 8.8 × 1018 to 1.9 × 1018 αdecays/g. A second suite of polycrystalline zircon samples that were synthesized 16 years ago with 10.0 wt.% Pu was also investigated. The 239Pu238Pu isotopic ratio in these samples resulted in α-activities of 2.5 × 108 and 5.6 × 1010 Bq/g and an accumulated dose of 1.2 × 1017 and 2.8 × 1019 α-decays/g. The multicomponent composition of the simulated waste glass permitted XAFS investigation at six elemental absorption edges. For both the glass and ceramic waste forms, initial analysis of Extended X-Ray Absorption Fine Structure (EXAFS) and X-Ray Absorption Near Edge Structure (XANES) indicate that the local environment around the cations exhibit different degrees of disorder as a result of the accumulated a-decay dose. In general cations with short cationoxygen bonds show little effect from self-radiation where as cations with long cation-oxygen bonds show a greater degree of disorder with accumulated a-decay dose.

X-ray absorption near-edge structure and extended x-ray absorption fine-structure investigation of Pd silicides

1985 ◽  
Vol 32 (2) ◽  
pp. 612-622 ◽  
Author(s):  
M. De Crescenzi ◽  
E. Colavita ◽  
U. Del Pennino ◽  
P. Sassaroli ◽  
S. Valeri ◽  
...  
Keyword(s):  
Fine Structure ◽  
Structure Investigation ◽  
Edge Structure ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

Tracking of arsenics during the thermal stabilization of an AsH3 scrubber sludge

2013 ◽  
Vol 68 (9) ◽  
pp. 2007-2011 ◽  
Author(s):  
Chang-Yu Liao ◽  
Fang-Chih Chang ◽  
H. Paul Wang ◽  
Yu-Ling Wei ◽  
Chih-Ju G. Jou
Keyword(s):  
Fine Structure ◽  
High Temperature ◽  
Thermal Stabilization ◽  
Bonding Energy ◽  
Edge Structure ◽  
X Ray ◽  
Temperature Range ◽  
Absorption Fine ◽  
X Ray Absorption ◽  
Exafs Spectra

Toxic arsenics in an AsH3 scrubber sludge were thermally stabilized in the temperature range of 973–1,373 K. To better understand how the high-temperature treatments can stabilize arsenics in the sludge, their synchrotron X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra of arsenics were determined. It is found that the reduced arsenic leachability may be associated with the formation of As2O5 (51–59%) and embedded As(V) within the Ca3(PO4)2 matrix (41–49%) in the stabilized sludge. In addition, the As-O bond distances in the stabilized As2O5 are much less than that of normal As2O5 by 0.05–0.07 Å. The shorter As-O bond distances accompanied with the higher bonding energy also have a contribution to the thermal stabilization of arsenics.

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