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A multi-edge study of the local structure of lithium borate glasses and melts has been carried out using X-ray Raman scattering (XRS) as a function of temperature. Thanks to a wide range of compositions, from pure B 2 O 3 up to the metaborate composition, we are able to finely interpret in detail the modifications of the local environment of both the boron and oxygen atoms in terms of boron coordination number, formation of non-bridging oxygens (NBOs) and polymerization's degree of the borate framework as a function of temperature and composition. A temperature induced [4] B to [3] B conversion is observed above the glass transition temperature (T g ) from the glass to the melt from the triborate composition up to the metaborate composition. Two distinct melt structures are reported: a well polymerized borate network -with few NBOs -below the triborate composition, and a depolymerized borate network above the diborate composition with a rapid increase of the number of NBOs when Li 2 O is added. These two structurally distinct melts allow explaining the two dynamical regimes observed for lithium ion diffusion.

The first colour photographs were created by ap rocess introduced by Edmond Becquerel in 1848. The nature of these photochromatic images colours motivated ad ebate between scientists during the XIX th century,w hich is still not settled. We present the results of chemical analysis (EDX, HAXPES and EXAFS) and morphology studies (SEM, STEM) aiming at explaining the optical properties of the photochromatic images (UV-visible spectroscopya nd low loss EELS). We rule out the two hypotheses (pigment and interferences) that have prevailed since 1848, respectively based on variations in the oxidation degree of the compound forming the sensitized layer and periodically spaced photolytic silver planes.Astudy of the silver nanoparticles dispersions contained in the coloured layers showed specific localizations and sizes distributions of the nanoparticles for each colour. These results allowustoformulate aplasmonic hypothesis on the origin of the photochromatic images colours.

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We characterize experimentally and theoretically the high-energy dielectric screening properties of the prototypical correlated metal SrVO 3 . The dynamical structure factor measured by inelastic x-ray scattering spectroscopy as a function of momentum transfer is in very good agreement with first-principles calculations in the adiabatic local-density approximation to time-dependent density-functional theory. Our results reveal the crucial importance of crystal local fields in the charge response function of correlated materials: They lead to depolarization effects for localized excitations and couple spectra from different Brillouin zones.