Ultrafast Multidimensional Spectroscopy: A Window into Proton-Coupled Electron Transfer and its Control

This perspective discusses the application of multidimensional spectroscopies in the study of electron transfer, proton transfer, and proton-coupled electron transfer (PCET) processes in the excited state. By addressing vibrational modes intimately tied to the reaction coordinate, these techniques aim to probe, perturb, and ultimately steer photochemical reactions. Simultaneously, multidimensional spectroscopies will provide unparalleled insight into these processes, accessing observables not available to conventional ultrafast spectroscopy. Altogether, this approach allows us to move beyond simple observation towards active manipulation of fundamental chemical reactions in the excited state.