Probing Spin-Polarised Paramagnetic States by Time-Resolved EPR Spectroscopy

Photoexcitation of molecules often leads to paramagnetic states that are formed in a non-Boltzmann regime far from the thermal equilibrium. These states show a rich spin dynamics and can be probed directly by using time-resolved electron paramagnetic resonance (TREPR) spectroscopy. This is a pump–probe experiment with the electron spin as probe and the EPR spectrometer as readout, correspondingly. We show how this method helps to elucidate radical pairs in cryptochromes that may play a role in animal navigation.[1] Furthermore, we give insights into the structure-function relationship of organic semiconductors by investigating triplet excitons.[2] References[1] T. Biskup: Time-resolved EPR of radical pair intermediates in cryptochromes. Mol. Phys.,111:3698–3703, 2013[2] T. Biskup: Structure–function relationship of organic semiconductors: detailed insights fromtime-resolved EPR spectroscopy. Front. Chem. 7:10, 2019