Exploring electronic structure through high-resolution hard x-ray spectroscopies

Tuesday, July 23, 2013 - 11:00am

Presented by Dimosthenis Sokaras,
Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory

Modern high brilliance beamlines coupled with recent advances in hard-x-ray optics are establishing high-resolution hard x-ray spectroscopies as a powerful analytical tool for routine electronic structure investigations. Their advantageous characteristics like the chemical sensitivity or the hard x-rays penetration depth, that permits the implementation of difficult sample environments, expand the applicability of the relevant studies to multidisciplinary scientific fields. Simultaneously, the experimental advances and the improvements on the data quality are triggering continuous developments of the theoretical electronic structure calculations to support and strengthen the data interpretation.

Here, we will be discussing on the recently designed, built and operated high-resolution and large solid angle spectroscopy end-station at beamline 6-2 (SSRL). Three multicrystal high energy-resolution x-ray spectrometers (a 40-crystal low-q x-ray Raman spectrometer, a 14-crystal high-q x-ray Raman spectrometer and a 7-crystal x-ray emission spectrometer) enable high throughput XES, HERFD-XAS, RIXS and XRS experiments. Further on, a 16-crystal von Hamos spectrometer, designed for single shot time-resolved experiments, has been built and operated in the SSRL and the LCLS.

Research highlights to be presented include fundamental x-ray Raman studies on the electronic structure of lithium compounds and the covalency of metal-oxygen molecular compounds by means of DFT-based interpretations. Moreover, combination of static (SSRL) and ultrafast (LCLS) x-ray emission of Fe-Kβ is employed to reveal the dynamics of metal-to-ligand charge transfer processes on Fe complexes demonstrating the complementary character of synchrotron and XFEL experiments. Future research opportunities and plans enabled by the developed instrumentation will be discussed.

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