S.K. Frehan MSc (Sean)

PhD Candidate


Engineering & Materials Science
Plasmonic Nanoparticles
Precious Metals
Transition Metals
Physics & Astronomy
Metal Nitrides


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.


Eric, V., Li, X., Dsouza, L. , Frehan, S. K. , Huijser, A., Holzwarth, A. R., Buda, F., Sevink, G. J. A., de Groot, H. J. M., & Jansen, T. L. C. (2023). Manifestation of hydrogen bonding and exciton delocalization on the absorption and two-dimensional electronic spectra of chlorosomes. The Journal of physical chemistry B, 127(5), 1097-1109. Advance online publication. https://doi.org/10.1021/acs.jpcb.2c07143
O'Neill, D. B. , Frehan, S. K. , Zhu, K., Zoethout, E. , Mul, G., Garnett, E. , Huijser, A., & Askes, S. (2021). Ultrafast photoinduced heat generation by plasmonic HfN nanoparticles. Advanced Optical Materials, 9(19), Article 2100510. Advance online publication. https://doi.org/10.1002/adom.202100510

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University of Twente
Faculty of Science and Technology
Horst Complex (building no. 20), room ME150
De Horst 2
7522LW  Enschede
The Netherlands

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University of Twente
Faculty of Science and Technology
Horst Complex  ME150
P.O. Box 217
7500 AE Enschede
The Netherlands