Singlet fission has been analyzed with the Dexter model in which electron exchange occurs between chromophores, conserving the spin for each electron. In the present study, we propose a spin exchange model for singlet fission. In the spin exchange model, spins are exchanged by the exchange interaction between two electrons. Our analysis with simple spin functions demonstrates that singlet fission is possible by spin exchange. A necessary condition for spin exchange is a variation in exchange interactions. We also adapted the spin exchange model to triplet fusion and triplet energy transfer, which often occur after singlet fission in organic solids.

用Dexter模型分析了单重态裂变，其中发色团之间发生电子交换，从而使每个电子保持自旋。在本研究中，我们提出了单重态裂变的自旋交换模型。在自旋交换模型中，自旋通过两个电子之间的交换相互作用进行交换。我们对简单自旋函数的分析表明，通过自旋交换，单线态裂变是可能的。自旋交换的必要条件是交换相互作用的变化。我们还使自旋交换模型适用于三重态融合和三重态能量转移，这通常在有机固体中发生单重态裂变后发生。