Photoionization of microsolvated biomolecules – from valence electronic structure to intermolecular Coulombic decay

• Applicant: Dr. Sebastian Hartweg
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas ; Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 553684281

Most molecular systems that are important for chemical or biological processes occur naturally in solution or other condensed phases. However, in the field of molecular photoelectron and photoion spectroscopy, the most detailed insights are obtained from experiments in the gas phase, where photoelectrons can be detected unaffected by scattering processes and photoions and their molecular decay processes can be observed. We therefore propose to study the photoionization of microsolvated biomolecules and biomolecular clusters and the dynamic relaxation and fragmentation processes triggered by them. The study of solvation effects through the study of microsolvation complexes of a biomolecule and up to a few water molecules allows the application of the full toolkit of gas-phase photoionization techniques, including photoelectron and photoion (multi-)coincidence techniques. This molecular approach to the study of solvation and condensation effects has been successfully applied previously in a variety of fields, and we believe that recent advances in the capabilities of state-of-the-art large-scale radiation facilities in the XUV and X-ray ranges, as well as advances in electron and ion detection techniques, call for the application of this approach to study the photoionization of such microsolvated biomolecular systems. The photoionization of these systems and the dynamics which are triggered thereby are of fundamental importance for understanding radiation damage in biological tissues. In addition to the effects of solvation and clustering on the electronic structure and dissociative ionization channels of biomolecules, we will experimentally measure the detailed energetics and ultrafast dynamics of intermolecular Coulombic decay processes between solvent water and biomolecules. Such intermolecular Coulombic decay processes of unoccupied inner shells in water molecules can lead to the ionization of solvated biomolecules, and thus significantly contribute to radiation damage in biological material.

• DFG Programme: Research Grants