Surface-hopping dynamics coupled to linear response TDDFT and explicit nonadiabatic and spin–orbit couplings have been used to model the ultrafast intersystem crossing (ISC) dynamics in [Ru(bpy)₃]²⁺. Simulations using an ensemble of trajectories starting from the singlet metal-to-ligand charge transfer (¹MLCT) band show that the manifold of ³MLCT triplet states is first populated from high-lying singlet states within 26 ± 3 fs. ISC competes with an intricate internal conversion relaxation process within the singlet manifold to the lowest singlet state. Normal-mode analysis and principal component analysis, combined with further dynamical simulations where the nuclei are frozen, unequivocally demonstrate that it is not only the high density of states and the large spin–orbit couplings of the system that promote ISC. Instead, geometrical relaxation involving the nitrogen atoms is required to allow for state mixing and efficient triplet population transfer.

中文翻译：

---

[Ru（bpy）₃ ] ^2+中包括系统间交叉的表面跳线动力学

与线性响应TDDFT耦合的表面跳变动力学以及显式非绝热和自旋轨道耦合已被用于模拟[Ru（bpy）₃ ] ^2+中的超快速系统间穿越（ISC）动力学。使用从单重态金属到配体电荷转移（¹ MLCT）谱带开始的整体轨迹轨迹进行的仿真表明，³的流形首先从26±3 fs内的高位单重态填充MLCT三重态。ISC在单重态歧管到最低的单重态下与复杂的内部转化松弛过程竞争。正态模式分析和主成分分析，结合进一步的动力学模拟（其中核被冻结）明确地表明，促进ISC的不仅是系统的高密度密度和系统的大自旋轨道耦合。相反，需要涉及氮原子的几何弛豫以允许状态混合和有效的三重态种群转移。