Multi-dimensional photoelectron spectroscopy of solvated molecules

• Applicant: Dr. Oleg Kornilov
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2014 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 256008187

A novel multi-dimensional photoelectron spectroscopy will be developed and applied to the investigation of excited state dynamics in the photosynthetic Fenna-Matthews-Olson complex (FMO) in the condensed phase. In our method the molecules will be excited by a pair of phase-locked femtosecond laser pulses in the visible or near-IR range, with a variable delay. Next, a vacuum-ultraviolet (VUV) probe pulse (photon energies of 10-50 eV) will ionize the system and the generated photoelectrons will be detected by a photoelectron spectrometer. The technique is an extension of existing and widely used all-optical multi-dimensional spectroscopic techniques, and derives its strength from several advantages of VUV photoionization in the detection step: (i) the high sensitivity of charged particle (electron) detection, (ii) the lack of dark states in VUV photoionization, and (iii) the de-coupling of the excited state dynamics from that of the ground state and that of higher-lying excited states. The latter property will help addressing the highly debated distinction between electronic and vibrational coherences in FMO, since the electronic coherence leads to oscillations within the manifold of the detected excited states, while the vibrational coherence also affects the ground state dynamics. The experiments will be carried out using a novel femtosecond VUV photoelectron spectroscopy beamline and a novel liquid microjet experimental apparatus, which were recently completed at the Max-Born-Institute. To the best of our knowledge, this represents the first time that a multi-dimensional spectroscopic technique is experimentally implemented using photoelectron spectroscopy.

• DFG Programme: Research Grants
• Major Instrumentation: high-resolution broadband pulse shaper
• Instrumentation Group: 5770 Lichtmodulatoren, Elektrooptik, Magnetooptik
• Participating Person: Professor Dr. Marc Vrakking