The City College of the City University of New York
160 Convent Avenue
New York, NY 10031

Physics Department
email: physdept@ccny.cuny.edu
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Wednesday, March 9, 2021 from 04:00 PM to 05:00 PM

Where By Zoom

Contact Name Ronald Koder

Contact Phone 212-650-5583

Physics Colloquium

Electron Spin Polarization in Rigid, Coupled Triplet-Doublet Pairs 

Arthur J. van der Est
Professor of Chemistry and Adjunct Professor of Physics

Brock University, Ontario, Canada

Research

Our research focuses on using modern time-resolved electron spin resonance (ESR) spectroscopy to study the structure and function of photosynthetic reaction centres and porphyrin-based model systems. Light excitation of these systems leads to energy and electron transfer reactions involving short-lived paramagnetic intermediates. The spin polarized transient EPR spectra of these species can be used to deduce both structural as well as kinetic information about the functional states.

Our interest in photosynthesis involves understanding how plants and bacteria capture and store sunlight. In particular, we are trying to elucidate the role that protein-cofactor interactions play in controlling the efficiency and rate of the transmembrane electron transfer in photosynthetic reaction centres. Transient ESR is especially well-suited for studying the quinone acceptors in these systems and has shown that protein-cofactor interactions have a dramatic influence on the properties of the quinones different in different reaction centres.

The work on porphyrin-based model systems is directed primarily towards mimicking the natural photosystems and creating complexes that are able to use visible light to oxidize water. Together with Prof. Prashanth Poddutoori we have been studying complexes based on main group element porphyrins that are able to act as the photosensitizers in high potential photoanodes.