Miura Tomoaki, Maeda Kiminori, Arai Tatsuo
Department of Chemistry, Faculty of Science, Shizuoka University, Ohya 836, Shizuoka City 422-8529, Japan.
J Phys Chem A. 2006 Mar 30;110(12):4151-6. doi: 10.1021/jp056488d.
The spin mixing process of the radical pair in the sodium dodecyl sulfate (SDS) micelle is studied by using a novel technique nanosecond pulsed magnetic field effect on transient absorption. We have developed the equipment for a nanosecond pulsed magnetic field and observed its effect on the radical pair reaction. A decrease of the free radical yield by a reversely directed pulsed magnetic field that cancels static field is observed, and the dependence on its magnitude, which is called pulsed MARY (magnetic field effect on reaction yield) spectra, is studied. The observed spectra reflect the spin mixing in 50-200 ns and show clear time evolution. Theoretical simulation of pulsed MARY spectra based on a single site modified Liouville equation indicates that the fast spin dephasing processes induced by the modulation of electron-electron spin interaction by molecular reencounter affect to the coherent spin mixing by a hyperfine interaction in a low magnetic field.
通过使用一种关于瞬态吸收的新型技术——纳秒脉冲磁场效应，研究了十二烷基硫酸钠（SDS）胶束中自由基对的自旋混合过程。我们开发了用于纳秒脉冲磁场的设备，并观察了其对自由基对反应的影响。观察到反向定向的脉冲磁场消除静磁场时自由基产率降低，并研究了其对磁场强度的依赖性，即所谓的脉冲MARY（磁场对反应产率的效应）光谱。观察到的光谱反映了50 - 200纳秒内的自旋混合，并显示出明显的时间演化。基于单位点修正的刘维尔方程对脉冲MARY光谱进行的理论模拟表明，分子重遇引起的电子 - 电子自旋相互作用调制所诱导的快速自旋去相过程，在低磁场中会影响超精细相互作用导致的相干自旋混合。
