Floquet theory of radical pairs in radiofrequency magnetic fields
Floquet theory of radical pairs in radiofrequency magnetic fields
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DOI：
10.1063/1.4963793
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发表时间：
2016-09-28
影响因子：
4.4
通讯作者：
Hore, P. J.
中科院分区：
文献类型：
--
作者：
Hiscock, Hamish G.;Kattnig, Daniel R.;Hore, P. J.
我们提出了一种新方法，用于计算在弱时间依赖性磁场存在下自由基对重组反应的产物产率。该方法成功地克服了直接求解包含许多超精细耦合核自旋的长寿命自由基对的刘维尔-冯·诺依曼方程所带来的计算困难。使用 Floquet 理论的修改公式，将随时间变化的磁场视为扰动，并利用缓慢的自由基对重组，我们表明，通过仅考虑 Floquet 空间的近简并子空间，可以获得产物产率的良好近似值。在重要的参数范围内，发现所得到的方法给出的产物产率与各种简单模型自由基对的精确量子力学结果非常一致。此外，它比精确计算效率要高得多，并且可以应用于包含更多核自旋的自由基对。这有望为射频电磁辐射对鸟类视网膜中光化学诱导的自由基对重组反应的影响的现实理论研究打开大门，该反应被认为是候鸟磁罗盘感觉的原因。由 AIP 出版社出版。
We present a new method for calculating the product yield of a radical pair recombination reaction in the presence of a weak time-dependent magnetic field. This method successfully circumvents the computational difficulties presented by a direct solution of the Liouville-von Neumann equation for a long-lived radical pair containing many hyperfine-coupled nuclear spins. Using a modified formulation of Floquet theory, treating the time-dependent magnetic field as a perturbation, and exploiting the slow radical pair recombination, we show that one can obtain a good approximation to the product yield by considering only nearly degenerate sub-spaces of the Floquet space. Within a significant parameter range, the resulting method is found to give product yields in good agreement with exact quantum mechanical results for a variety of simple model radical pairs. Moreover it is considerably more efficient than the exact calculation, and it can be applied to radical pairs containing significantly more nuclear spins. This promises to open the door to realistic theoretical investigations of the effect of radiofrequency electromagnetic radiation on the photochemically induced radical pair recombination reactions in the avian retina which are believed to be responsible for the magnetic compass sense of migratory birds. Published by AIP Publishing.