Solvated dielectrons from optical excitation: An effective source of low-energy electrons

Low-energy electrons dissolved in liquid ammonia or aqueous media are powerful reducing agents that promote challenging reduction reactions but can also cause radiation damage to biological tissue. Knowledge of the underlying mechanistic processes remains incomplete, particularly with respect to the details and energetics of the electron transfer steps. In this work, we show how ultraviolet (UV) photoexcitation of metal-ammonia clusters could be used to generate tunable low-energy electrons in situ. Specifically, we identified UV light-induced generation of spin-paired solvated dielectrons and their subsequent relaxation by an unconventional electron transfer-mediated decay as an efficient, low-energy electron source. The process is robust and straightforward to induce with the prospect of improving our understanding of radiation damage and fostering mechanistic studies of solvated electron reduction reactions.

Automated summary

Low-energy electrons dissolved in liquid ammonia or aqueous media can serve as powerful reducing agents but can also cause radiation damage to biological tissue. The mechanistic processes underlying electron transfer steps are still not fully understood. This study demonstrates how ultraviolet (UV) photoexcitation of metal-ammonia clusters can be used to generate tunable low-energy electrons. The UV light-induced generation of spin-paired solvated dielectrons and their subsequent relaxation through unconventional electron transfer-mediated decay offer an efficient source of low-energy electrons. This process has the potential to improve our understanding of radiation damage and facilitate mechanistic studies of solvated electron reduction reactions.