In the process, chloranil firstly was excited to singlet state and then a labile hydrogen abstraction interaction between singlet chloranil and β-diketones was involved to form singlet stable neutral radical pairs ( RP). 光照作用下,四氯苯醌首先跃迁至单线态,然后夺取β二酮类化合物分子中的活泼氢,形成单线态中性自由基对。