Photoemission Spectroscopy Group

Our research group focuses on the development and application of advanced liquid-phase photoemission spectroscopy using liquid microjets in vacuum (Liquid-Jet Photoemission Spectroscopy). This method is unique in many respects. It is the only technique capable of providing the complete electronic structure of molecules directly in solution while also exhibiting high surface sensitivity. In addition, it captures processes on an ultrafast timescale and enables mapping of specific electronic relaxation pathways that occur exclusively in liquids.

The core of our work lies in the synergy between state-of-the-art experiments and theoretical modeling. Due to the need for high-quality soft X-ray radiation, our experiments are conducted at leading European synchrotron facilities, including BESSY II and DESY in Germany, MAX IV in Sweden, and SOLEIL in France. The experimental data are then closely integrated with quantum-chemical calculations, which help us to interpret fundamental microscopic processes in detail or even predict the behavior of the studied systems.

This comprehensive methodological approach enables us to investigate a broad range of chemically relevant phenomena. For example, we focus on ion pairing and the structure of solvation shells, which is of fundamental importance in areas ranging from biological receptors to the development of advanced ionic batteries. By exploiting Auger-type electronic relaxation processes, we analyze specific non-covalent interactions and study biochemical interactions in solution. We also investigate acid–base processes in biologically relevant systems (e.g., in enzymatic pathways of the citric acid cycle), where, thanks to the ultrafast nature of photoionization, we study proton sharing and (de) localization as a function of pH. Our research further extends into atmospheric chemistry and nuclear separation processes, where we determine the surface concentration and orientation of molecules at liquid–air and liquid–liquid interfaces.