0000000000352151

AUTHOR

P. Lagarde

showing 4 related works from this author

Tetrahedral versus octahedral Mn site coordination in wurtzite and rocksalt Zn1−xMnxO investigated by means of XAS experiments under high pressure

2007

Abstract We present the results of x-ray absorption measurements carried out in Zn 1− x Mn x O thin films under high pressure. The Mn environment remains essentially the same for nominal Mn concentrations given by x = 0.05 , 0.1, 0.15 and 0.25. Both the XANES (X-ray Absorption Near Edge Structure) and EXAFS (Extended X-ray Absorption Fine Structure) indicate that Mn occupies the Zn site, being surrounded by four oxygen atoms at 2.02±0.01 A. The substitutional hypothesis is reinforced by comparing the differences between the ambient (wurtzite) and high pressure (rocksalt) spectra, which correspond to tetrahedral and octahedral Mn environments.

010302 applied physicsX-ray absorption spectroscopyMaterials scienceExtended X-ray absorption fine structure02 engineering and technology021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciencesXANESSpectral lineX-ray absorption fine structureCrystallographyOctahedron0103 physical sciencesGeneral Materials ScienceElectrical and Electronic EngineeringAbsorption (chemistry)0210 nano-technologyWurtzite crystal structureSuperlattices and Microstructures
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Sodium Adsorption on the TiO2110 Surface an XAFS Structural Study

2005

The adsorption site of sodium atoms deposited onto a clean TiO2(110) surface has been determined by EXAFS. The best result is obtained for an 'in-between' site where the sodium is bound to two bridging oxygen atoms at 2.25 A and one in-plane one at 2.40 A in full agreement with DFT calculations. At higher coverage the site becomes a hollow site where Na is equidistant to the three oxygen atoms at 2.30 A.

Surface (mathematics)Materials scienceExtended X-ray absorption fine structureSodiumchemistry.chemical_elementCondensed Matter PhysicsAtomic and Molecular Physics and OpticsX-ray absorption fine structureBridging oxygenOxygen atomAdsorptionchemistryPhysical chemistryEquidistantMathematical PhysicsPhysica Scripta
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The defined adsorption site of sodium on the TiO2(110)–(1×1) surface

2004

The adsorption site of sodium on the TiO2(1 1 0)–(1 × 1) surface was studied by extended X-ray absorption fine structure. For coverage ranging between 0.25 and 0.5 ML, we find that sodium is on an ‘in-between' site where it is bound to two bridging oxygen atoms at 2.25 Å and one in-plane oxygen atom at 2.40 Å, in full agreement with DFT calculations. At higher coverage the site becomes an hollow site where the sodium atom is equidistant to the three oxygen atoms at 2.30 Å, while metallic sodium clusters are also formed at the surface.

Alkali metalsSodiumInorganic chemistrychemistry.chemical_element02 engineering and technologyExtended X-ray absorption fine structure (EXAFS)01 natural sciencesOxygenMetalAdsorption0103 physical sciencesAtomMaterials Chemistry010306 general physicsTitanium oxideExtended X-ray absorption fine structureChemistrySurfaces and Interfaces021001 nanoscience & nanotechnologyCondensed Matter PhysicsAlkali metalSurfaces Coatings and FilmsCrystallographyvisual_artvisual_art.visual_art_mediumAbsorption (chemistry)0210 nano-technologySurface Science
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Interfacial reaction between deposited molybdenum and TiO2(110) surface: role of the substrate bulk stoichiometry

2004

Abstract The interfacial reaction between deposited molybdenum and three different TiO2(1 1 0) substrates (a bulk and surface stoichiometric TiO2; a bulk stoichiometric and surface reduced crystal; a bulk and surface slightly reduced crystal) was investigated by means of X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge spectroscopy (XANES). While the interfacial reaction is not a function of the substrate at room temperature (in any case, molybdenum layers grow with oxygen dissolved in), this study clearly reveals a strong effect of the substrate bulk stoichiometry on the chemical state of the deposit after annealing up to 750 °C whereas the substrate surface stoichiome…

X-ray absorption spectroscopyAnnealing (metallurgy)ChemistryAnalytical chemistrychemistry.chemical_elementSurfaces and InterfacesCondensed Matter PhysicsXANESSurfaces Coatings and FilmsMetalChemical stateX-ray photoelectron spectroscopyMolybdenumvisual_artMaterials Chemistryvisual_art.visual_art_mediumStoichiometrySurface Science
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