Spin Dynamics of Photogenerated Multi-Spin Systems

Fast photo-initiated electron transfer within covalently-linked organic donor-acceptor molecules having specific donor-acceptor distances and orientations results in the formation of spin-correlated radical pairs (SCRPs) having well-defined initial spin configurations and magnetic spin-spin interactions. Time-resolved EPR and pulse-EPR techniques will be used to manipulate, control, and observe these coherent spin states. Our new research will investigate how spin motion amongst multiple sites and the presence of additional spins influence the spin dynamics of SCRP’s and spin coherence using tailored covalent organic structures. The specific goals of this project are to investigate four questions that are important for understanding spin coherence in organic molecules and the development of organic spintronics: •How does spin sharing over multiple radical sites influence coherence dephasing in SCRPs? •Does electron transfer from a photoexcited stable radical to a distant site preserve spin coherence? •Can coherent spin states be propagated over long intramolecular distances using SCRPs? •Can a photo-generated SCRP provide a means of producing transient spin frustration?