Rostock 2019 – scientific programme
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MO: Fachverband Molekülphysik
MO 3: Ultrafast Processes in Solution
MO 3.5: Talk
Monday, March 11, 2019, 11:45–12:00, S HS 001 Biologie
Solvent-dependent time-resolved photoelectron spectroscopy study of relaxation dynamics in Quinoline Yellow — •Evgenii Ikonnikov, Johan Hummert, and Oleg Kornilov — Max-Born-Institute, Max-Born-Strasse 2A, Berlin, Germany
Relaxation dynamics of molecules often depends on their environment. In water, next to intramolecular relaxation processes, additional processes like solvent rearrangement and proton transfer upon photon absorption are possible. Recently we demonstrated pump-probe photoelectron spectroscopy in solution, which is a powerful tool for obtaining binding energies and lifetimes of molecular excited states of solvated molecules [1]. In our experiments we use a short XUV pulse as a probe pulse and 800/400 nm pulse as a pump pulse with pulse duration of 30 fs. In this contribution we will present measurements of relaxation dynamics of Quinoline Yellow (QY) in different solvents. In Ref. [1] we studied QY in water and observed three relaxation times: 250 ± 70 fs, 1.3 ± 0.4 ps and 90 ± 20 ps. We proposed that the two latter timescales may represent intramolecular proton transfer, while the fast timecale corresponds to solvent rearrangment. To clarify the nature of these processes we measure relaxation dynamics of QY in water with pH=9 and in heavy water to investigate the role of intermolecular proton transfer processes, which are expected to be slower for D2O. [1] J. Hummert, G. Reitsma, N. Mayer, E. Ikonnikov, M. Eckstein and O. Kornilov, J. Phys. Chem. Lett., 6649-6655, 9 (22), 2018.