Direct observation of ultrafast symmetry reduction during internal conversion of 2-thiouracil using Coulomb explosion imaging
Abstract
Abstract The photochemistry of heterocyclic molecules plays a decisive role for processes and applications like DNA photo-protection from UV damage and organic photocatalysis. The photochemical reactivity of heterocycles is determined by the redistribution of photoenergy into electronic and nuclear degrees of freedom, initially involving ultrafast internal conversion. Most heterocycles are planar in their ground state and internal conversion requires symmetry breaking. To lower the symmetry, the molecule must undergo an out-of-plane motion, which has not yet been observed directly. Here we show using the example of 2-thiouracil, how Coulomb explosion imaging can be utilized to extract comprehensive information on this molecular deformation, linking the extracted deplanarization of the molecular geometry to the previously studied temporal evolution of its electronic properties. Particularly, the protons of the exploded molecule are well-suited messengers carrying rich information on its geometry at distinct times after electronic excitation. We expect that our new analysis approach centered on these peripheral protons can be adapted as a general concept for future time-resolved studies of complex molecules in the gas phase.
Article Details
Authors (28)
Till Jahnke
European XFEL
Sebastian Mai
Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna , Währinger Straße 17, 1090 Vienna,
Surjendu Bhattacharyya
Stanford PULSE Institute
Keyu Chen
School of Materials Science and Engineering, State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Technology Innovation Center of High Performance Resin Materials (Liaoning Province)
Rebecca Boll
European XFEL , Holzkoppel 4 , ,
Maria Elena Castellani
Simon Dold
European XFEL , Holzkoppel 4 , ,
Ulrike Frühling
Alice E. Green
EaStCHEM School of Chemistry
Markus Ilchen
Deutsches Elektronen-Synchrotron DESY , Notkestr. 85 , ,
Rebecca Ingle
Gregor Kastirke
Institut für Kernphysik
Huynh Van Sa Lam
James R. Macdonald Laboratory, Physics Department
Fabiano Lever
Institut für Physik und Astronomie
Dennis Mayer
Deutsches Elektronen-Synchrotron DESY 2 , 22607 Hamburg,
Tommaso Mazza
Terence Mullins
European XFEL, Holzkoppel 4, Schenefeld 22869, Germany
Yevheniy Ovcharenko
Björn Senfftleben
European XFEL, Holzkoppel 4, Schenefeld 22869, Germany
Florian Trinter
Fritz-Haber-Institut der Max-Planck-Gesellschaft , , Faradayweg 4-6 , ,
Atia-Tul-Noor
Sergey Usenko
Anbu Selvam Venkatachalam
James R. Macdonald Laboratory, Physics Department
Artem Rudenko
James R. Macdonald Laboratory, Physics Department
Daniel Rolles
James R. Macdonald Laboratory, Physics Department
Michael Meyer
Heide Ibrahim
Markus Gühr
Institut für Physik und Astronomie