Bonn 2025 – scientific programme
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MO: Fachverband Molekülphysik
MO 25: X-ray Spectroscopy
MO 25.4: Talk
Thursday, March 13, 2025, 15:30–15:45, HS XVI
XUV Double-Ionisation of Micro-Solvated Bio-relevant Molecules — •Brendan Wouterlood1, Sitanath Mondal1, Myriam Drissi2, Madhusree Roy-Chowdhury2, Gustavo Garcia-Marcias2, Laurent Nahon2, Frank Stienkemeier1, and Sebastian Hartweg1 — 1Institute of Physics, University of Freiburg — 2Synchrotron SOLEIL, St. Aubin, France
Studying the XUV-photoionisation of biomolecules, such as the nucleobase thymine and its precursor, pyridine, in the gas phase allows detailed insights into energetics and dynamics at the molecular level. As in-vivo biomolecular systems exist in the condensed phase, studying complexes of these molecules with water gives greater insight into decay channels that are available in biological systems, while still allowing the application of typical gas phase experimental approaches such as electron-ion coincidence spectroscopy. The electron-ion-ion coincidence detection of doubly-ionised molecules and complexes enables correlation of cationic states to certain fragmentation pathways. Above the double-ionisation potential, molecular fragmentation channels differ from single ionisation processes with intramolecular proton transfer reactions stabilising the cationic fragments. In these complexes different auto-ionisation processes, such as the non-local intermolecular Coulombic decay (ICD) and electron transfer mediated decay (ETMD), and local Auger-Meitner decay can thus be distinguished. These processes are important to the field of radiation chemistry since the production of low energy electrons can trigger reactions which damage biological material.
Keywords: Photoelectron Photoion Coincidence Spectroscopy; Microsolvation; Nucleobases; Auto-ionisation; Biomolecules