0000000000759500

AUTHOR

P. Fornasini

showing 2 related works from this author

X-ray absorption spectroscopy of strongly disordered glasses: Local structure around Ag ions ing−Ag2O∙nB2O3

2006

The local structure around Ag ions in silver borate glasses $g\text{\ensuremath{-}}{\mathrm{Ag}}_{2}\mathrm{O}∙n{\mathrm{B}}_{2}{\mathrm{O}}_{3}$ $(n=2,4)$ was studied by x-ray absorption spectroscopy at the Ag $K$ edge for temperatures from $77\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}450\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Extended x-ray absorption fine structure (EXAFS) analysis based on cumulant expansion or multishell Gaussian model fails for these systems. Therefore, the radial distribution functions (RDFs) around Ag ions were reconstructed using a method based on the direct inversion of the EXAFS expression. The RDFs consist of about eight atoms (oxygens and b…

X-ray absorption spectroscopyMaterials scienceAbsorption spectroscopyExtended X-ray absorption fine structurechemistry.chemical_elementCondensed Matter PhysicsXANESElectronic Optical and Magnetic MaterialsX-ray absorption fine structureIonCrystallographychemistryAbsorption (logic)Atomic physicsBoronPhysical Review B
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X-ray absorption spectroscopy study of local dynamics and thermal expansion in ReO3

2015

The thermal expansion of polycrystalline ${\mathrm{ReO}}_{3}$ is studied in vacuum by x-ray diffraction from 300 to 600 K and by extended x-ray absorption fine structure (EXAFS) at the Re ${L}_{3}$ edge from 30 to 600 K. A detailed EXAFS analysis is presented up to the sixth coordination shell around Re. The crystal thermal expansion is weak throughout the explored range, negative below 100 K, positive from 150 to 500 K, and negative again above 500 K. The analysis of mean square relative displacements obtained by EXAFS and of mean square displacements available from x-ray and neutron diffraction measurements confirms the presence of significant static disorder in the investigated samples. …

X-ray absorption spectroscopyMaterials scienceCondensed matter physicsExtended X-ray absorption fine structureNeutron diffractionCondensed Matter PhysicsThermal expansionReO3; X-RAY ABSORPTION FINE-STRUCTURE; MULTIPLE-SCATTERING; DIFFRACTION MEASUREMENTS; LATTICE-DYNAMICS; PRESSURE; EXAFS; NEGATIVE THERMAL EXPANSIONElectronic Optical and Magnetic MaterialsCrystalEXAFSNegative thermal expansionRigid unit modesLocal dynamicsAbsorption (logic)Thermal expansionThermal expansion EXAFS Local dynamics
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