Department Atomic-Scale Dynamics in Light-Energy Conversion

Beamtimes

Steve was in very good hands with the local team, Mayro and Robert. Bernd Winter from the Frith-Haber-institute in Berlin also visited us several times and provided valuable support during the measurements, as well as with cleaning the vacuum chamber and preparing the cold traps. © Robert Seidel, Stephen Bradforth

Week 11-12 2026 (March 10 – 22) – Stephen E. Bradforth (USC Los Angeles)

Proposal no: 261-20333 ST

Stephen Bradforth from the University of Southern California (USC) was awarded two weeks of beamtime to investigate subtle shifts in the absolute binding energies of core and valence orbitals in biologically relevant DNA nucleosides and their derivatives, as well as resonant Auger emission following core excitation at the nitrogen and oxygen K-edges. These highly ambitious measurements are expected to provide new insights into the behavior of core-to-π* excited DNA bases in aqueous solution. This is particularly important because the unoccupied π* orbitals of nucleobases play a key role in the UV absorption of DNA and, consequently, in UV-induced photodamage.

Thanks to Michael Müller from the BESSY II User Service, we used the BESSY overhead crane to maneuver our SOL³PES unit into its final position at the beamline. Mayro was happy at first, then became attentive as the machine was lowered. Together, we then attached the heavy feet to the machine. © Fanny Getzlaff / Robert Seidel @ HZB

Week 10 2026 (March 03 – 08) – Seidel group (Helmholtz-Zentrum Berlin)

Proposal no: 261-20090 EF part I

This was the first official beamtime carried out with our newly upgraded SOL³PES setup. Following the installation and careful alignment of the experimental system, we investigated the electronic structure of CeO₂ nanoparticles suspended in water as a function of stabilizer concentration. We also studied the concentration- and depth-dependent dissociation equilibria between carbonate (CO₃²⁻) and bicarbonate (HCO₃⁻), probing different distances from the liquid surface.