Multiplicity-controlled photochemical processes

Excited state multiplicity plays a critical role in governing photochemical reactivity. Most of the excited organic molecules can exist either in the singlet or triplet excited state. Singlets are typically short-lived (~ns) and exhibit zwitterionic character, whereas triplet excited states, with their diradical-like nature, are significantly longer-lived (~μs–ms), enabling diffusion-controlled intermolecular processes. The contrasting photochemical behaviour of singlets and triplets has been mostly understood phenomenologically, with their lifetimes and zwitterionic or diradical-like character often cited as key factors. However, the intrinsic reason for this behaviour difference, electronic spin, is often neglected in the rationalization of photochemical reactivity. The PhD candidate will address this gap by designing and studying multiplicity-controlled photoreactions based on fundamental principles, reflecting spin-spin interactions and spin-selection rules.

Study program: Organic chemistry