Technical University of Denmark / Lund University

This poster will present results from some of the first combined time-resolved x-ray scattering and x-ray emission spectroscopy measurements conducted at the two operational Hard X-ray Free Electron Laser sources. The studies have focused on elucidating the relationship between electronic kinetics and molecular structural dynamics during electron transfer and spin-relaxation processes in both bimetallic photocatalytic model complexes and in a set of iron containing spin-crossover systems in solution. The combination of the x-ray emission and transient optical absorption spectroscopy allow us to map the details of the electron transfer and spin relaxation pathways with femtosecond time- resolution. The simultaneously measured x-ray scattering data show how these processes drive large structural changes of the molecular species. Furthermore the scattering data is shown to provide a handle on solvent-solute interactions, flow of excess excitation energy and solvent dynamics, during the first few picoseco nds after the excitation event. An example of the information extracted from these combined measu rements is given in Figure 1, for the case of the bimetallic photocatalytic model compound.