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A newly designed setup to perform steady-state X-ray excited optical luminescence (XEOL) spectroscopy and simultaneous XEOL and X-ray absorption spectroscopy characterization at beamline P65 of PETRA III is described. The XEOL setup is equipped with a He-flow cryostat and state-ofthe- art optical detection system, which covers a wide wavelength range of 300– 1700 nm with a high spectral resolution of 0.4 nm. To demonstrate the setup functioning, low-temperature XEOL studies on polycrystalline CuInSe2 thin film, single-crystalline GaN thin film and single-crystalline ZnO bulk semiconductor samples are performed.

The structure of Ge20Sb10S70, Ge23Sb12S65 and Ge26Sb13S61 glasses was investigated by neutron diffraction (ND), X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS) measurements at the Ge and Sb K-edges as well as Raman scattering. For each composition, large scale structural models were obtained by fitting simultaneously diffraction and EXAFS data sets in the framework of the reverse Monte Carlo (RMC) simulation technique. Ge and S atoms have 4 and 2 nearest neighbors, respectively. The structure of these glasses can be described by the chemically ordered network model: Ge-S and Sb-S bonds are always preferred. These two bond types adequately describe the structure of the stoichiometric glass while S-S bonds can also be found in the S-rich composition. Raman scattering data show the presence of Ge-Ge, Ge-Sb and Sb-Sb bonds in the S-deficient glass but only Ge-Sb bonds are needed to fit diffraction and EXAFS datasets. A significant part of the Sb-S pairs has 0.3-0.4 angstrom longer bond distance than the usually accepted covalent bond length (similar to 2.45 angstrom). From this observation it was inferred that a part of Sb atoms have more than 3 S neighbors., Struktura skel Ge20Sb10S70, Ge23Sb12S65 a Ge26Sb13S61 byla zkoumána měřeními neutronové difrakce (ND), rentgenové difrakce (XRD), extended X-ray absorption fine structure (EXAFS) na Ge a Sb K-hranách a Ramanovým rozptylem. Pomocí současně fitovaných dat z difrakce a EXAFS v rámci reverzní Monte Carlo (RMC) simulační techniky byly pro všechna složení získány strukturní modely ve velkém měřítku. Ge a S atomy mají 4 a 2 nejbližší sousedy. Struktura těchto skel může být popsána chemicky uspořádaných modelem sítě: Ge-S a Sb-S vazby jsou vždy preferovány. Tyto dva typy vazeb adekvátně popisují strukturu stechiometrických skel, zatímco vazby S-S mohou být nalezeny u složení bohatého S. Data Ramanova rozptylu ukazují přítomnost vazeb Ge-Ge, Ge-Sb a Sb-Sb ve sklech s deficitem S, ale pouze vazby Ge-Sb jsou nutné pro fitování difrakčních a EXAFS dat. Významná část párů Sb-S má o 0.3-0.4 angstromu delší vazby než obvykle akceptovaná délka kovalentní vazby (ca 2.45 angstromu). Na základě tohoho pozorování bylo vyvozeno, že část atomů Sb má více než 3 sousední atomy S.

We present element-specific effective bond-stretching force constants and Einstein frequencies of (In,Ga)P ternary alloys determined by temperature-dependent extended x-ray absorption fine structure spectroscopy. The bond-stretching force constants of both bond species show a nearly linear composition dependence between the values of GaP and InP. In contrast, the corresponding Einstein frequencies are different for the two bond species over the whole compositional range. Furthermore, we demonstrate that the composition dependence of bond-stretching force constants and Einstein frequencies for (In,Ga)P, (In,Ga)As, and Zn(Se,Te) is mostly caused by the associated bond length changes. Remaining deviations may be explained by coupling effects between different bond species within the alloy.

Round robin studies have been used across fields of science for quality control testing and to investigate laboratory dependencies and cross-platform inconsistencies as well as to drive forward the improvement of understanding of experimental systems, systematic effects and theoretical limitations. Here, following the Q2XAFS Workshop and Satellite to IUCr Congress 2017 on `Data Acquisition, Treatment, Storage - quality assurance in XAFS spectroscopy', a mechanism is suggested for a suitable study across XAFS (X-ray absorption fine-structure) beamlines and facilities, to enable each beamline to cross-calibrate, provide representative test data, and to enable collaborative cross-facility activities to be more productive.

Copyright © 2015 Hydrogen Energy Publications, LLC.NaAlH4 was melt infiltrated within a CO2 activated carbon aerogel, which had been preloaded with TiCl3. Nanoconfinement was verified by Small Angle X-Ray Scattering (SAXS) and the nature of the Ti was investigated with Anomalous SAXS (ASAXS) and X-Ray Absorption Near Edge Structure (XANES) to determine its size and chemical state. The Ti is found to be in a similar state to that found in the bulk Ti-doped NaAlH4 system where it exists as Al1-xTix nanoalloys. Crystalline phases exist within the carbon aerogel pores, which are analysed by in-situ Powder X-Ray Diffraction (PXD) during hydrogen cycling. The in-situ data reveals that the hydrogen release from NaAlH4 and its hydrogen uptake occurs through the Na3AlH6 intermediate when confined at this size scale. The hydrogen capacity from the nanoconfined NaAlH4 is found to initially be much higher in this CO2 activated aerogel compared with previous studies into unactivated aerogels.