6533b86efe1ef96bd12cc9e2
RESEARCH PRODUCT
XANES and EXAFS modelling of configurational disorder in silver borate glasses
Ondřej ŠIprPaolo FornasiniFrancesca MontiAlexei KuzminF. RoccaAndrea SansonGiuseppe Dalbasubject
X-ray absorption spectroscopyMaterials scienceAbsorption spectroscopyExtended X-ray absorption fine structureilver borate glasseschemistry.chemical_elementX-ray absorption spectroscopyCondensed Matter PhysicsMolecular physicsAtomic and Molecular Physics and OpticsXANESSpectral lineCondensed Matter::Materials ScienceX-ray absorption spectroscopy; ilver borate glasses; model structuresK-edgechemistrymodel structuresMultiplicity (chemistry)BoronMathematical Physicsdescription
The sensitivity of X-ray absorption spectroscopy (XAS) to the local structure around a selected atomic species (symmetry, distances and angles) is commonly exploited to quantitatively describe systems where all the configurations around the absorbing atoms may be approximated by the mean one. However, in many cases of disordered systems a simple description of the local structure with singleconfiguration models cannot be reconciled with experimental spectra. In this paper the necessity to analyse the XAS spectra by considering a multiplicity of atomic structural configurations is demonstrated in the case of silver borate glasses. The local coordination around Ag cations in (Ag2O.nB2O3) glasses has been studied by comparing the XAS experimental spectra at the Ag K edge with theoretical XANES and EXAFS spectra obtained by a configurational average of model structures. In order to provide a reasonable agreement with experiment, these models have to take into account that there are many geometrically distinct Ag neighbourhoods present in the system, and that the measured XANES and EXAFS signals are in fact averages over spectra originated at all the non-equivalent photoabsorbing sites (multi-configuration approach).
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2005-01-01 |