Coherent Photochemical Reactions in Sequential Molecular Systems-Measurement and Theoretical Formulation

通过实验测量和理论推导，建立了高度组织化的分子体系的光化学反应的相干性质。主要结果如下：(1)首次观测到了激子在两个发色团之间的循环运动的量子拍频信号。这意味着激子在两个生色团之间相干地来回移动，分子系统中的光化学反应在电子退相干之前在几个ps内相干地发生。研究了外加电场作用下的相干光化学反应，发现该反应受外加电场的控制。几种类型的一维卟啉(Osuka化合物)阵列在光激发下表现出显著的电导增强。(3)建立了植物光合作用反应中心(RC)电子和激子相干传输的理论模型，并将高阶微扰理论应用于RC蛋白中分子的循环和顺序排列。综上所述，本研究计划取得了90%的成功。

The Coherent nature of photochemical reaction has been established for highly organized molecular systems through the experimental mesurement and theoretical formulation. The results are summarized as follows.(1) The first observation of quantum beat signal has been attained for cyclic motion of exciton between two chromophores inanthracene dimers and perylene dimers. This means that the exciton moves coherently back and forth between the two chromophores, and that the photochemical reaction in molecular systems occurs coherently in several ps before the electronic decoherence. A special apparatus was constructed which was capable of quantum-interference control of the reaction.(2) The coherent photochemical reaction under external electric field was investigated, and found that the reaction was controlled by applying electric field. Several types of porphyrin arrays of 1D (Osuka compounds) exhibited a significant enhancement of conductivity upon photoexcitation. These molecular systems may function as molecular wires switchable by photo-irradiation.(3) The theoretical formulation has been established for coherent transports of electron and exciton in photosynthetic reaction centers (RC) in plants A higher-order perturbation theory was applied to the cyclic and sequential arrangements of molecules inside the RC proteins.In Summary, the present reserch project has attained 90% success for the reserch program that we planned initially.