Bonn 2025 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

MO: Fachverband Molekülphysik

MO 5: Ultrafast Dynamics I

MO 5.8: Vortrag

Dienstag, 11. März 2025, 12:45–13:00, HS XVI

Probing UV-induced dynamics of phenanthridine with time-resolved X-ray absorption and X-ray photoelectron spectroscopy — •Dorothee Schaffner¹, Constant Schouder², Kira Diemer¹, Xincheng Miao¹, Emil Karaev¹, Dennis Mayer³, Audrey Scognamiglio², Andre Al Haddad⁴, Antoine Sarracini⁴, Gregor Knopp⁴, Lou Barreau², Lionel Poisson², Patrick Hemberger⁴, Kirsten Schnorr⁴, Roland Mitric¹, and Ingo Fischer¹ — ¹University of Würzburg, Germany — ²ISMO, Paris-Saclay University, France — ³DESY, Hamburg, Germany — ⁴PSI, Villigen, Switzerland

Modifying polycyclic aromatic hydrocarbons (PAHs) by replacing a carbon by a nitrogen atom introduces nπ* states into the molecules, in addition to existing ππ* states. This leads to an alteration in optoelectronic properties making nitrogen-containing PAHs (PANHs) promising candidates e.g. for organic photovoltaic devices. In this experiment we investigated the excited state dynamics of the PANH phenanthridine after UV excitation into the S3 state (ππ* character). Using the Maloja endstation at SwissFEL, time-resolved X-ray absorption and photoelectron spectra were recorded near the N1s edge that are particularly sensitive towards nπ* states. Significant shifts are observed in the time-resolved spectra and time constants for the deactivation process were derived. Spectral features of the excited states and time constants are compared to theoretical results from surface hopping dynamics simulations combined with TDDFT calculations.

Keywords: X-ray absorption spectroscopy; X-ray photoelectron spectroscopy; time-resolved spectroscopy; pump-probe spectroscopy; free electron laser