scholarly journals Local environment and valence state of iron in microinclusions in fibrous diamonds: X-ray Absorption and Mössbauer data

2010 ◽  
Author(s):  
Andrei Shiryaev
Keyword(s):  
Valence State ◽  
Local Environment ◽  
X Ray ◽  
Mössbauer Data ◽  
X Ray Absorption

Local environment and valence state of iron in microinclusions in fibrous diamonds: X-ray absorption and Mössbauer data

2010 ◽  
Vol 51 (12) ◽  
pp. 1262-1266 ◽  
Author(s):  
A.A. Shiryaev ◽  
Y.V. Zubavichus ◽  
A.A. Veligzhanin ◽  
C. McCammon
Keyword(s):  
Valence State ◽  
Local Environment ◽  
X Ray ◽  
Mössbauer Data ◽  
X Ray Absorption

VALENCE STATES AND LOCAL ENVIRONMENT OF THALLIUM AND COPPER IONS IN SOME NEW HIGH Tc SUPERCONDUCTORS BY XAS

1989 ◽  
Vol 03 (07) ◽  
pp. 1085-1096 ◽  
Author(s):  
F. STUDER ◽  
R. RETOUX ◽  
C. MARTIN ◽  
C. MICHEL ◽  
B. RAVEAU ◽  
...  
Keyword(s):  
Valence State ◽  
Copper Ions ◽  
Local Environment ◽  
X Ray Diffraction ◽  
High Tc Superconductors ◽  
High Tc ◽  
X Ray ◽  
Valence States ◽  
X Ray Absorption ◽  
Thallium Ions

The valence states of cations inside four high T c thallium superconductors have been investigated by X-ray absorption spectroscopy at thallium LIII , LI and copper K-edges. The thallium ions are observed on LIII and LI edges in the Tl(III) valence state (empty 6s levels) in spite of large Tl-O distances in the (a, b) plane of the structure as deduced from X-ray diffraction. The presence of two types of Tl-O distances have been well established on XANES spectra and the F.T. of EXAFS have shown the presence of two very short Tl-O bonds (2.03 Å). The copper K-edges are characterized by the absence of Cu(I) state (3d10 line).

Titanium environment in TiO2–BaO–ZnO–B2O3 glasses by x-ray absorption spectroscopy

2000 ◽  
Vol 15 (3) ◽  
pp. 793-797 ◽  
Author(s):  
N. Watanabe ◽  
A. Y. Ramos ◽  
M. C. M. Alves ◽  
H. Tolentino ◽  
O. L. Alves ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Local Environment ◽  
Titanium Content ◽  
Optical Performance ◽  
X Ray ◽  
X Ray Absorption

The local environment of titanium in glasses of the system TiO2–BaO–ZnO–B2O3 was studied by x-ray absorption spectroscopy. In all glasses, for TiO2 content varying from 35 to 49 mol%, the titanium atoms are mainly fourfold coordinated network formers. For the glass with the highest titanium content, about 20% of the titanium enters into a sixfold environment, indicating the presence of precrystalline nuclei. These nuclei are responsible for the decrease of the optical performance of the glass above threshold titanium content, prior to any observable crystallization.

scholarly journals Preliminary investigation of chlorine speciation in zirconolite glass-ceramics for plutonium residues by analysis of Cl K-edge XANES

MRS Advances ◽  
2019 ◽  
Vol 5 (1-2) ◽  
pp. 37-43
Author(s):  
Amber R. Mason ◽  
Stephanie M. Thornber ◽  
Martin C. Stennett ◽  
Laura J. Gardner ◽  
Dirk Lützenkirchen-Hecht ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Absorption Edge ◽  
Glass Ceramic ◽  
Glass Phase ◽  
Preliminary Investigation ◽  
Glass Ceramics ◽  
Local Environment ◽  
Aluminosilicate Glass ◽  
X Ray ◽  
X Ray Absorption

ABSTRACTA zirconolite glass-ceramic material is a candidate wasteform for immobilisation of chlorine contaminated plutonium residues, in which plutonium and chlorine are partitioned to the zirconolite and aluminosilicate glass phase, respectively. A preliminary investigation of chlorine speciation was undertaken by analysis of Cl K-edge X-ray Absorption Near Edge Spectroscopy (XANES), to understand the incorporation mechanism. Cl was found to be speciated as the Cl- anion within the glass phase, according to the characteristic chemical shift of the X-ray absorption edge. By comparison with Cl K-edge XANES data acquired from reference compounds, the local environment of the Cl- anion is most closely approximated by the mineral marialite, in which Cl is co-ordinate to 4 x Na and/or Ca atoms.

scholarly journals Valence state fossils in Proterozoic stromatolites by L-edge X-ray absorption spectroscopy

2007 ◽  
Vol 112 (G3) ◽  
pp. n/a-n/a ◽  
Author(s):  
Stephen J. Brotton ◽  
Russell Shapiro ◽  
Gerrit van der Laan ◽  
Jinghua Guo ◽  
Per-Anders Glans ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Valence State ◽  
X Ray ◽  
X Ray Absorption

Extended x-ray absorption fine structure study of incorporation of Bi and Pb atoms into the crystal structure of Ba4.5Nd9Ti18O54

1997 ◽  
Vol 12 (3) ◽  
pp. 799-804 ◽  
Author(s):  
M. Valant ◽  
I. Arčon ◽  
D. Suvorov ◽  
A. Kodre ◽  
T. Negas ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Fine Structure ◽  
Local Environment ◽  
Structure Study ◽  
X Ray ◽  
Absorption Fine ◽  
Exafs Study ◽  
X Ray Absorption

In the extended x-ray absorption fine structure (EXAFS) study of the local environment of Bi3+ and Pb2+ ions incorporated in Ba4.5Nd9Ti18O54, actual sites of Bi- and Pb-incorporation are determined. Evidence is given that dopant ions are not distributed randomly on all theoretically possible sites; Bi3+ selectively enters one out of three possible channels, corresponding to the sites x = 0.9484, y = 0.2500, z = 0.2939, and/or x = 0.0455, y = 0.2500, z = 0.6928 previously occupied by Nd3+, while Pb2+ selectively enters site x = 0.4940, y = 0.2500, and z = 0.4993 previously shared by Ba2+ and Nd3+.

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