Multidimensional interferometric photoelectron spectroscopy with extreme ultraviolet photons

2026-07-22

Photochemical reactions are the central driving force in nature and in sustainable technologies. Understand-ing photochemical reactions on the quantum level is thus a primary goal in science. However, this task re-mains a major experimental and theoretical challenge even on the single-molecule level due to the involved ultrafast time scales, predominantly nonradiative processes and strongly coupled degrees of freedom. Methods are needed that provide a gap-less view on the molecular mechanisms with the necessary sensitivity and selectivity to uncover and disentangle the participating reaction pathways. In this project, we will for the first time establish ultrafast multidimensional extreme ultraviolet (XUV) photoelectron spectroscopy to solve this problem. This method is capable of mapping photochemical processes with unprecedented spec-tro-temporal resolution along the entire reaction coordinate, while unraveling otherwise degenerate path-ways in multidimensional correlation maps. This becomes possible with the unique combination of concepts from coherent multidimensional spectroscopy with femto to attosecond XUV light sources and photoelectron spectroscopy. As spectroscopic probes, well-controlled model systems will be investigated, ranging from isolated, cold molecules and molecular complexes to individual species embedded in tailored nano-cluster environments. The proposed project will (a) establish laboratory-based high-resolution XUV photoelectron spectroscopy as a widely accessible alternative to experiments at synchrotron and free-electron-laser facilities (b) introduce the concept of coherent multidimensional photoelectron spectroscopy (c) develop new theoreti-cal analysis methods of transient multidimensional photoelectron data (d) resolve the details of fundamental intra and intermolecular photochemical processes including elusive non-adiabatic and quantum coherence mechanisms (e) elucidate the role of tailored environments in molecular dynamics.

Germany

2025-10-01