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Precise control and characterization of nanomaterials at working conditions are essential for further rational applications in many areas important for modern society. Penetrating properties of X-ray radiation in combination with advanced spectroscopy schemes are an ideal tool to investigate modifications of nanomaterials with extraordinary precision. Here, we present preliminary results on the controlled oxidation of copper nanoparticles and exploration of X-ray absorption spectroscopy to follow electronic and structural changes. The described pilot experiment raises questions on the applicability of high energy resolution X-ray detection schemes in potential future investigations aimed at following reversible reduction/oxidation processes at nanoparticle surfaces. [ABSTRACT FROM AUTHOR]

In the probe-before-destroy methodology, developed with the advent of X-ray free-electron lasers, the investigated system is probed with an ultra-short (femtosecond) X-ray pulse within time shorter than that the X-ray-induced damage needs to propagate. Radiation damage is typically considered in terms of the Coulomb explosion which needs about 50 fs to induce observable effects in the material structure. It has been, however, shown that the much faster electronic structure change has also a significant influence on the X-ray emission spectroscopy data and may alter the X-ray diffraction patterns. This work reports on energy and time distribution of photo-electrons induced in water by an X-ray pulse with properties typical for an X-ray free-electron laser operated in the intensity regime below the sequential photoionization regime. The electron flux was simulated on the basis of a kinetic model and was found to be significant over the course of the X-ray pulse duration. The presented findings call for consideration of the X-ray-induced electrons in studies on solutions and samples embedded in matrices. [ABSTRACT FROM AUTHOR]