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Abstract: X-ray Absorption Spectroscopy (XAS), X-Ray Diffraction (XRD), Thermo-Gravimetric Analysis (TGA) and Scanning Electron Microscopy–Energy Dispersive Spectroscopy (SEM–EDS) techniques were used to determine the composition and the speciation of Fe and Mn in road dust samples collected in the Traforo del San Bernardo highway tunnel. Principal Component Analysis and Least Square Fitting on the XANES region of the absorption spectra and structural refinements on the EXAFS part of the spectra were applied to obtain complementary information on the speciation, average oxidation state, and local structure of Fe and Mn. XRD indicated the presence of silica, calcite, gypsum, and of various phyllosilicates. TGA analysis confirmed the presence of phyllosilicates and also detected a significant amount of organic phases. These findings indicate the co-presence of particles of natural origin along with the organic phases related to vehicular gas exhausts emission. On the other hand, XAS analysis showed that iron is mainly present in the Fe3O4 and FeCl3 forms, which can be considered to have both anthropic origin, i.e., exhaust emission and salt used to prevent ice formation, respectively. [Copyright &y& Elsevier]

We report on a non-destructive study of Sicilian ceramic fragments of cultural heritage interest, classified as 'proto-majolica' pottery and dating back to the twelfth to thirteen centuries AD. The analytical approach used is based on the employment of two totally non-invasive spectroscopic techniques: X-ray fluorescence (XRF), using a portable energy-dispersive XRF analyser, and X-ray absorption spectroscopy, using synchrotron radiation as a probe (SR-XAS). XRF measurements allowed us to collect elemental and spatially resolved information on major and minor constituents of the decorated coating of archaeological pottery fragments, so providing preliminary results on the main components characterizing the surface. In particular, we assigned to Fe and Mn the role of key elements of the colouring agent. With the aim of obtaining more detailed information, we performed SR-XAS measurements at the Fe and Mn K-edges at the Italian BM08 beamline at the European Synchrotron Radiation Facility (Grenoble, France). The experimental data were analysed by applying principal component analysis and least-squares fitting to the near-edge part of the spectra (X-ray absorption near-edge structure) to determine the samples' speciation. From the overall results, umber, a class of brownish pigments characterized by a mixture of hydrated iron and manganese oxides, has been ascribed as a pigmenting agent. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: Mn-K edge EXAFS and XANES spectra of La0.87Na0.13MnO3 manganite films with different thicknesses (750, 250, 125 and 50Å), have been acquired at RT. In the 50Å film a shift of the Fermi level downward in energy is found if compared to the other films. In addition, the density of the empty minority spin states is decreased. This finding has been attributed to the presence of some Mn ions experiencing a different local chemical environment that results in the breaking of some DE paths, and in addition to an Anderson localisation of the charge carriers. This last conclusion can explain both the strongly insulating nature and the spin glass like behaviour of the magnetic response of the 50Å film, and has been corroborated by the results of the EXAFS analysis. [Copyright &y& Elsevier]