X-ray absorption near edge structure and first-principles spectral investigations of cationic disorder in MgAl2O4 induced by swift heavy ions

2018 ◽  
Vol 20 (7) ◽  
pp. 4962-4969 ◽  
Author(s):  
S. Yoshioka ◽  
K. Tsuruta ◽  
T. Yamamoto ◽  
K. Yasuda ◽  
S. Matsumura ◽  
...  
Keyword(s):  
First Principles ◽  
Heavy Ions ◽  
Edge Structure ◽  
X Ray ◽  
Swift Heavy Ions ◽  
X Ray Absorption ◽  
Cationic Disorder

Cationic disorder in MgAl2O4 induced by swift heavy ions was quantitatively determined using experimental and theoretical XANES spectra.

scholarly journals Structural relaxations around Ti, Cr and Fe impurities in α-Al2O3probed by x-ray absorption near-edge structure combined with first-principles calculations

2005 ◽  
Vol 17 (36) ◽  
pp. 5467-5480 ◽  
Author(s):  
Emilie Gaudry ◽  
Delphine Cabaret ◽  
Philippe Sainctavit ◽  
Christian Brouder ◽  
Francesco Mauri ◽  
...  
Keyword(s):  
First Principles ◽  
First Principles Calculations ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption ◽  
Fe Impurities

scholarly journals First-principles modeling of X-ray absorption spectra enlightens the processes of scandium sequestration by iron oxides

2020 ◽  
Vol 105 (7) ◽  
pp. 1099-1103 ◽  
Author(s):  
Mathieu Chassé ◽  
Marc Blanchard ◽  
Delphine Cabaret ◽  
Amélie Juhin ◽  
Delphine Vantelon ◽  
...  
Keyword(s):  
Trace Metals ◽  
Iron Oxides ◽  
Absorption Spectra ◽  
First Principles ◽  
Molecular Mechanisms ◽  
Hydration Shell ◽  
Spectral Features ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

Abstract Scandium is often associated with iron oxides in the environment. Despite the use of scandium as a geochemical tracer and the existence of world-class supergene deposits, uncertainties on speciation obscure the processes governing its sequestration and concentration. Here, we use first-principles approaches to interpret experimental K-edge X-ray absorption near-edge structure spectra of scandium either incorporated in or adsorbed on goethite and hematite, at concentrations relevant for the environment. This modeling helps to interpret the characteristic spectral features, providing key information to determine scandium speciation when associated with iron oxides. We show that scandium is substituted into iron oxides at low concentrations without modifying the crystal structure. When scandium is adsorbed onto iron oxide surfaces, the process occurs through outer-sphere complexation with a reduction in the coordination number of the hydration shell. Considering available X-ray absorption spectra from laterites, the present results confirm that scandium adsorption onto iron oxides is the dominant mechanism of sequestration in these geochemical conditions. This speciation explains efficient scandium recovery through mild metal-lurgical treatments of supergene lateritic ores. The specificities of scandium sorption mechanisms are related to the preservation of adsorbed scandium in million-years old laterites. These results demonstrate the emerging ability to precisely model fine X-ray absorption spectral features of trace metals associated with mineral phases relevant to the environment. It opens new perspectives to accurately determine trace metals speciation from high-resolution spatially resolved X-ray absorption near-edge structure spectroscopy in order to constrain the molecular mechanisms controlling their dynamics.

scholarly journals Correction: X-ray absorption near edge structure simulation of LiNi0.5Co0.2Mn0.3O2via first-principles calculation

RSC Advances ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 3882-3882
Author(s):  
Toshiharu Ohnuma ◽  
Takeshi Kobayashi
Keyword(s):  
First Principles ◽  
First Principles Calculation ◽  
Edge Structure ◽  
X Ray ◽  
Structure Simulation ◽  
X Ray Absorption

Correction for ‘X-ray absorption near edge structure simulation of LiNi0.5Co0.2Mn0.3O2via first-principles calculation’ by Toshiharu Ohnuma et al., RSC Adv., 2019, 9, 35655–35661.

scholarly journals X-ray absorption near edge structure simulation of LiNi0.5Co0.2Mn0.3O2via first-principles calculation

RSC Advances ◽  
2019 ◽  
Vol 9 (61) ◽  
pp. 35655-35661 ◽  
Author(s):  
Toshiharu Ohnuma ◽  
Takeshi Kobayashi
Keyword(s):  
First Principles ◽  
First Principles Calculation ◽  
Edge Structure ◽  
X Ray ◽  
Structure Simulation ◽  
X Ray Absorption

Simulation of Ni K-edge X-ray absorption near edge structure (XANES) spectra in LiNi0.5Co0.2Mn0.3O2 (NCM523) was performed.

scholarly journals Influence of crystallographic environment on scandium K-edge X-ray absorption near-edge structure spectra

2018 ◽  
Vol 20 (37) ◽  
pp. 23903-23912 ◽  
Author(s):  
Mathieu Chassé ◽  
Amélie Juhin ◽  
Delphine Cabaret ◽  
Steven Delhommaye ◽  
Delphine Vantelon ◽  
...  
Keyword(s):  
Physical Chemistry ◽  
First Principles ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

First Sc K-edge XANES spectra calculations using first-principles methods to explore the physical chemistry of this elusive element.

Further findings of X-ray absorption near-edge structure in lithium manganese spinel oxide using first-principles calculations

2014 ◽  
Vol 2 (21) ◽  
pp. 8017-8025 ◽  
Author(s):  
Toyoki Okumura ◽  
Yoichi Yamaguchi ◽  
Masahiro Shikano ◽  
Hironori Kobayashi
Keyword(s):  
First Principles ◽  
Dft Calculation ◽  
Structural Characteristics ◽  
Lithium Ion ◽  
First Principles Calculations ◽  
Edge Structure ◽  
X Ray ◽  
Lithium Manganese ◽  
X Ray Absorption ◽  
Lithium Manganese Spinel

DFT calculation reveals that local structural characteristics in lithium manganese spinel oxides such as lithium ion displacement change due to phase transition can be detected from XANES spectra.

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