Bonn 2025 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
MO: Fachverband Molekülphysik
MO 20: Poster – Molecular Spectroscopy and Dynamics
MO 20.22: Poster
Wednesday, March 12, 2025, 17:00–19:00, Tent
Coulomb explosion imaging of molecular photoswitches — Kieran Cheung1, Arnaud Rouzee2, Claus Peter Schulz2, Till Jahnke3, David Busto4, Per Eng-Johnsson5, Rebecca Boll6, Marc J. J. Vrakking1, Giuseppe Sansone4, Daniel Rolles7, Michael Meyer6, Terry Mullins6, Mark Brouard1, and •Kasra Amini2 — 1Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK — 2Max-Born-Institut, Max-Born-Straße 2A, 12489 Berlin, Germany — 3Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany — 4Physikalisches Institut, Universität Freiburg, 799104 Freiburg, Germany — 5Department of Physics, Lund University, Lund, Sweden — 6European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany — 7J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Kansas 66506, USA
We present an X-ray Coulomb explosion imaging (CEI) investigation into the photofragmentation and photochemistry of trans-4,4′-difluoroazobenzene (DFAB) using the COLTRIMS Reaction Microscope at the SQS station of the European XFEL. We show a systematic analysis of X-ray-induced fragmentation in DFAB, employing covariance techniques to explore fragmentation dynamics. We then report time-resolved measurements of DFAB excited to its first electronic excited state (S1) under varying visible pump excitation conditions. Our findings highlight the limited propensity of trans-DFAB to undergo trans-to-cis isomerization following S1 excitation and reveal the emergence of a dissociative ionization process leading to photodissociation.
Keywords: Coulomb explosion imaging; Ultrafast isomerization; Femtochemistry; Ultrafast molecular dynamics; Femtosecond photochemistry