Magnetic Field Effects (MFEs) on the recombination of radicals, which diffuse on an infinite plane, are studied theoretically. The case of spin-selective diffusion-controlled recombination of Radical Pairs (RPs) starting from a random spin state is considered assuming uniform initial distribution of the radicals. In this situation, reaction kinetics is described by a time-dependent rate coefficient K(t), which tends to zero at long times. Strong MFEs on K(t) are predicted that originate from the Δg and hyperfine driven singlet-triplet mixing in the RP. The effects of spin relaxation on the magnetic field are studied, as well as the influence of the dipole-dipole interaction between the electron spins of the RP. In the two-dimensional case, this interaction is not averaged out by diffusion and it strongly affects the MFE. The results of this work are of importance for interpreting MFEs on lipid peroxidation, a magnetosensitive process occurring on two-dimensional surfaces of cell membranes.

中文翻译：

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磁场对在二维平面上扩散的自由基复合的影响。

从理论上研究了自由基在无穷大平面上扩散时对自由基复合产生的磁场效应（MFE）。考虑自由基的均匀初始分布，考虑从随机自旋态开始的自旋选择性扩散控制的自由基对的扩散对重组（RPs）。在这种情况下，反应动力学由随时间变化的速率系数K（t）来描述，该系数长期趋于零。预测K（t）上的强MFE源自RP中的Δg和超精细驱动的单重态-三重态混合。研究了自旋弛豫对磁场的影响，以及RP电子自旋之间的偶极-偶极相互作用的影响。在二维情况下，这种相互作用不能通过扩散来平均，并且会严重影响MFE。