本文描述了我们两人最近提出的自由基对复合反应的半经典理论[D。E. Manolopoulos和P. J. Hore，J.Chem.Phys.139，124106（2013）]可以一般化以允许不同的单线态和三线态重组速率。这是一个非平凡的概括，因为当复合速率不同时，复合过程动态地耦合到自由基对的相干电子自旋动力学。此外，由于复合算符是一个双电子算符，仅仅把两个电子看作经典矢量是不够的：必须把16个双电子自旋算符的完整集合看作独立的经典变量。由此产生的半经典理论的第一次验证了一个模型自由基对包含12个核自旋的精确量子力学结果的比较。然后，它被用来阐明含有相当多的核自旋的类胡萝卜素-卟啉-富勒烯（CPF）三元组的自旋动力学，该三元组最近被用来建立化学罗盘操作的“原理证明”[K. Maeda等人，Nature 453，387（2008）]。我们发现，特别是有趣的两相行为，已观察到的地球强度的磁场的光激发的C+PF-自由基对随时间变化的生存概率的影响，从它的不对称重组和放松类胡萝卜素自由基的电子自旋之间的微妙平衡。
英文摘要：
We describe how the semiclassical theory of radical pair recombination reactions recently introduced by two of us [D. E. Manolopoulos and P. J. Hore, J. Chem. Phys. 139, 124106 (2013)] can be generalised to allow for different singlet and triplet recombination rates. This is a non-trivial generalisation because when the recombination rates are different the recombination process is dynamically coupled to the coherent electron spin dynamics of the radical pair. Furthermore, because the recombination operator is a two-electron operator, it is no longer sufficient simply to consider the two electrons as classical vectors: one has to consider the complete set of 16 two-electron spin operators as independent classical variables. The resulting semiclassical theory is first validated by comparison with exact quantum mechanical results for a model radical pair containing 12 nuclear spins. It is then used to shed light on the spin dynamics of a carotenoid-porphyrin-fullerene (CPF) triad containing considerably more nuclear spins which has recently been used to establish a 'proof of principle' for the operation of a chemical compass [K. Maeda et al., Nature 453, 387 (2008)]. We find in particular that the intriguing biphasic behaviour that has been observed in the effect of an Earth-strength magnetic field on the time-dependent survival probability of the photo-excited C+PF- radical pair arises from a delicate balance between its asymmetric recombination and the relaxation of the electron spin in the carotenoid radical.
Recombination of Geminate (OH,eaq-) Pairs in Concentrated Alkaline Solutions: Lack of Evidence For Hydroxyl Radical Deprotonation
在200 nm的光解氢氧化物水溶液和400 nm（3光子）电离的水在浓碱性溶液中产生的水合电子和羟基自由基的皮秒动力学。在亚纳秒时间尺度上没有观察到羟基自由基的去质子化，即使在1-10 M KOH溶液中也是如此。这一结果与稀碱溶液中OH自由基去质子化的动力学数据完全不一致。我们认为，在浓碱性溶液中，羟基自由基的去质子化反应大大减慢。
