Investigation of the effects of microwave electromagnetic field on the reaction dynamics of radical ion pairs

微波辐照可诱导组成自由基的电子自旋共振，影响自由基对的反应动力学。这是由于微波的磁性成分的影响。另一方面，电场对材料的影响一般要比磁场大得多。因此，微波对自由基离子对的辐照可以引起电磁波的电分量和磁分量的双重作用。这也是目前引起公众关注的电磁场化学效应的一个例子。为了研究电和磁组分对反应的独立贡献，我们开发了一个双模腔，可以将每个组分应用于样品。对于2-甲基-1,4-萘醌在十二烷基硫酸钠胶束溶液中形成中性（不变）自由基对的光反应，我们再次证实了磁性组分与双腔的贡献。在相同的条件下，我们没有发现电气元件的显著影响。对于10-甲基吩噻嗪与1,4-二硝基苯形成自由基离子对的光反应，发现在kW功率范围内微波脉冲照射下，逸出的自由基离子的消失迟滞率提高了~ 2%。这种效应与磁场无关，排除了电子自旋共振的可能性。为了产生没有初始自旋相关的自由基离子对，我们研究了有机电致发光材料（OLED）的发射过程。我们发现磁场对这些荧光发光材料的发射强度有明显的影响。对这种依赖关系的分析表明，这种荧光的主要来源不是单线态自由基离子对复合产生的直接发射，而是在高工作电压下三重态自由基离子对复合形成的三重态激子碰撞产生的延迟荧光。共振微波的辐照降低了发射强度，说明了磁分量对发射过程的贡献。少

The reaction dynamics of radical pair is affected by the irradiation of microwave which can induce the electron spin resonance of the component radicals. This is due to the effect of magnetic component of microwave. On the other hand, the effect of electric field to materials is generally much larger than that of magnetic field. Therefore, the microwave irradiation to the radical ion pair may induce both of the effects of electric and magnetic components of electromagnetic wave. This is also an example of the chemical effect of electromagnetic field, which is now occupying the public interest. To investigate the independent contribution of electric and magnetic component to the reaction, we developed a dual mode cavity which can apply each of the components to samples. For the photoreaction of 2-methyl-1,4-naphthoquinone in sodium dodecylsulfate micellar solution, forming a neutral (changeless) radical pair, we reconfirmed the contribution of the magnetic component with the dual cavity … More . At the same condition, we could not find significant effect of the electric component. For the photoreaction of 10-methylphenothiazine with 1,4-dicyanobenzene, forming a radical ion pair, we found 〜2% increase of the retardation of the disappearance of escaped radical ions at the irradiation of the microwave pulse in a kW range power. This effect was independent of the magnetic field, excluding the possibility of electron spin resonance.In order to generate a radical ion pair without initial spin correlation, we investigated the emission process of the organic electroluminescence materials(OLED). We found a clear magnetic field effect on the emission intensify of these fluorescent EL materials. The analysis of this dependence revealed that the main origin of this fluorescence of is not the direct emission due to the recombination of singlet radical ion pair but the delayed fluorescence due to the collision of triplet excitons formed in the recombination of triplet radical ion pair at high operating voltages. The irradiation of resonant microwave reduced the emission intensity, which shows the contribution of magnetic component to the emission process. Less