Quantification of non-bridging oxygens in silicates using X-ray Raman scattering

Tandem CO2 Valorization and Ethane Dehydrogenation: Elucidating the Nature of Highly Selective Iron Oxide Active Sites

“…To further investigate the potential structural modifications occurring upon reaction and involving geometry/coordinational changes, Quantum Espresso (QE) DFT code and its Xspectra module, along with FDMNES, , were used for sake of consistency. The theoretical relaxed structure of ideal geometries combining octahedral and tetrahedral structural arrangements were used to calculate O K-edge spectra. , The parameters applied for the self-consistent field (SCF) calculations are summarized in Table S.2 in the Supporting Information. A constant rigid energy shift of 535 eV was applied to all the calculated spectra in order to match the energy range of the experimental data.…”

“…The theoretical relaxed structure of ideal geometries combining octahedral and tetrahedral structural arrangements were used to calculate O K-edge spectra. 41,42 The parameters applied for the self-consistent field (SCF) calculations are summarized in Table S.2 in the Supporting Information. A constant rigid energy shift of 535 eV was applied to all the calculated spectra in order to match the energy range of the experimental data.…”

X-ray Raman Scattering: A Hard X-ray Probe of Complex Organic Systems

“…While the most commonly used X-ray spectroscopy methods to study low- Z elements are conventional XAS techniques using soft X-rays, there are certain samples and sample conditions, where the application of more penetrating hard X-rays is advantageous and in some cases critical. XRS offers this capability and can be performed in situ and operando ,,− (e.g., using a chemical reaction cell, using a plug-flow reactor), under extreme conditions (e.g., using a furnace or diamond anvil cell) (refs − , , , , , − , , , − , − , and − ), under ambient conditions (atmospheric pressure, regular humidity and room temperature), and in its natural phase (solid, liquid, or gas). ,− As hard X-rays penetrate deep into the sample, it does not have to be surface-cleaned or diluted (needed for example to avoid saturation in fluorescence yield-detected XAS). XRS thus overcomes several difficulties related to the soft X-ray probe of conventional low- Z XAS techniques,...…”

“…The last two decades have seen the rapid development of XRS-based research for the study of low-energy edge transitions for a variety of organic materials, − liquid systems − including water-based systems, − gases, − and crystals. ,− XRS has been also employed to access transitions beyond the dipole limit (i.e., multipole transitions) in light elements, − lanthanides, − and actinides. − Following the pioneering work by Mao et al, a considerable amount of work has been published on the in situ characterization of materials under high pressure via XRS, in which the samples under study are enclosed by diamond anvil cells and a gasket material. The goal of high pressure XRS studies is to probe variations in the bonding characteristics, orbital hybridization, oxidation state, and spin state to understand the local atomic structure and/or the changes of electronic structure of the materials under study .…”

Le verre : un matériau d’hier, d’aujourd’hui et de demain

“…3). La formation des oxygènes non-pontants se matérialise facilement dans les spectres Raman ou RMN du 29 Si [2,28,29] ou récemment par diffusion inélastique des rayons X [30,31]. Leurs proportions augmentent avec la teneur en sodium ce qui augmente les entités faiblement connectées, Q 3 , Q 2 …, contribuant à la diminution de la viscosité.…”