On Monday, 2 March 2020 at 4:15 p.m. in Physicum lecture hall B103 (W. Ostwaldi 1, Tartu)
Kristjan Kunnus (time-resolved X-ray spectroscopy specialist at UTIP, postdoc at Stanford University PULSE Institute)
Femtosecond Time-Resolved X-ray Spectroscopy and Scattering with X-ray Free Electron Lasers
X-ray Free Electron Laser (XFEL) light sources deliver high brightness and femtosecond duration X-ray pulses that have revolutionized the field of ultrafast science in the past ten years. In this talk I will discuss the current capabilities of pump-probe X-ray Emission Spectroscopy (XES) and X-ray Solution Scattering (XSS) at XFELs. Specifically, I will present results from a series of experiments where we investigated photoinduced excited state electron transfer and intersystem crossing dynamics in solvated Fe photosensitizer model complexes. These experiments track simultaneously electronic state and nuclear structure of the molecules, and allowed us to observe branching of electronic relaxation pathways and coherent nuclear wavepacket dynamics. In addition, I will discuss vibronic effects that emerge in time-resolved XES experiments and are necessary to interpret the ultrafast time-dependent signals.
Kristjan Kunnus received his B.Sc. and M.Sc. degree in Materials Science from University of Tartu, Estonia. In 2014, he received his Dr. rer. nat. degree in experimental physics from University of Potsdam in Germany for his work on soft X-ray spectroscopy of transition metal complexes in solution. His current research as a post-doctoral researcher in Stanford University and SLAC National Laboratory focuses on time-resolved X-ray experiments of photoinduced excited states dynamics in metal complexes.
The Physicum seminars are meant for a broad auditorium of physicists and materials scientists, as well as for interested people from other natural and exact sciences (including bacheleor level students) and aim at introducing what is important and new in a certain field, or where a specific reasearch direction has reached today.
Everybody is welcome to attend.