Whether vibronic coupling, the coupling of photoinduced electronic and nuclear vibrational motion, plays a vital role or not in long-range exciton transfer is not yet understood. I study the impact vibrational modes may have on long-range exciton transfer by employing a number of spectroscopic techniques on chlorosomes, a rod-shaped light harvesting antenna composed of self-assembled bacteriochlorophyll molecules found in green sulphur bacteria.
These bacteria can survive under extremely low light conditions due to their highly efficient exciton transport. I have set up an optical unit including a pulse shaper to produce a complex femtosecond pulse shape enabling to perturb a selected vibrational mode. The dependency of the exciton transfer rate on the pulse shape will provide strong evidence for the significance of quantum coherence.
This research is in collaboration with the groups of Prof. Huub de Groot (Leiden) and Dr. Thomas Jansen (Groningen) and funded by a TOP grant from NWO Chemical Sciences.