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, in particular with respect to the details and energetics of the electron transfer steps. Here, 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.

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来自光激发的溶剂化双电子：低能电子的有效来源

溶解在液氨或水介质中的低能电子是强大的还原剂，可促进具有挑战性的还原反应，但也会对生物组织造成辐射损伤。对潜在机械过程的了解仍然不完整，特别是在电子转移步骤的细节和能量方面。在这里，我们展示了如何利用金属-氨簇的紫外（UV）光激发来原位产生可调谐的低能电子。具体来说，我们确定了紫外光诱导的自旋配对溶剂化双电子的产生及其随后通过非常规电子转移介导的衰变作为有效的低能电子源的弛豫。该过程稳健且易于诱导，