EXAFS at high temperature

Due to their sensitivity toward atmosphere, the sample conditioning had to preserve the sample from oxides or moisture interactions, and the surrounding from any linkages of vaporization of the sample, especially in actinides containing fluoride mixtures. A pellet was made of a mixture of boron nitride (BN) and sample powders, and pressed up to 61. This pellet was put between two plates in pyrolitic boron nitride, fixed hermetically with stainless steel screws. Thanks to their small size and simple geometry, inert toward molten fluorides and compatible with high temperature up to 1700 K and X-ray transmission, these cells fit easily in different furnaces [14]. 

Experimental EXAFS measurements presented in this paper were performed in transmission geometry at the zirconium K-edge and thorium Llll-edge on DIFFABS beamUne of the SOLEIL synchrotron in Gif-Sur-Yvette (France) and on BL27B beamline of the Photon Factory (PF), KEK in Tsukuba (Japan), respectively. 

The preparation of the pellets, furnaces, and devices used and the way of acquisition of the EXAFS oscillations are described in our previous papers [5, 8, 9, 14], The EXAFS oscillations were extracted by using Athena software following the usual way. 

The interaction potential used in these simulations derives from the polarizable ion model [15]. It can be described as the sum of four different contributions charge-charge, dispersion, overlapped repulsion, and polarization, as previously described by Salanne et al. [16].This code is dedicated to calculations in ionic liquids. Via classical MD calculations, it allows generating the trajectories of ions inside a periodically replicated simulation cell, and then extracting the relevant physico-chemical properties of the melt. 

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Recently characterization of bimetallic nanoparticles by EXAFS were extensively reported [122-124,176], Structural transformation of bimetallic Pd/Pt nanoparticles, which were prepared by a sequential loading of H2PtClg onto the Pd loaded catalyst, was investigated with EXAFS at high temperatures [176], The results of EXAFS at Pd K and Pt L-III edges showed that Pt was surface-enriched or anchored on the Pd metal core with an increase of the Pt content. The structure of the obtained bimetallic Pd/Pt nanoparticles seemed to be retained upon heating up to 1273 K under ambient condition [176], Pt/ Au bimetallic nanoparticles can be prepared by polyol method and stabilized by PVP [122], XANES and EXAFS studies were also performed on the samples and their results supported the idea of a Pt-core/Au-shell structure with the elements segregated from each other [122],... 

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