Theoretical Studies on the electron transser mechanism and the dynamics in the photosynthetic reaction

光合作用在地球上产生了大量的能量，这在生命活动和人类工业活动的起源中基本上都是重要的。在这个项目中，为了从理论上阐明光合作用反应的机理，我们首先研究了各种卟啉化合物和位于光合作用反应中心的特殊对的基态和激发态，然后研究了涉及周围蛋白质和氨基酸影响的光合作用反应中心的电子传递机制。首先，我们研究了各种卟啉化合物的基态和低激发态，包括镁卟啉、游离碱四氮杂吗啉、游离碱酞菁、氧血红素、羧基血红素、马萝卜过氧化氢CO、游离碱氯仿、游离碱细菌素、邻菲罗啉和叶绿素。SAC-CI计算准确地再现了这些化合物的光谱。我们提出了一些新的理论归属，并解释了这些光谱趋势的起源。接下来，我们研究了整个光合作用反应中心的激发光谱，以及光合作用反应中心的电子传递机制。我们计算了光合作用反应中心的所有元素，并从理论上对光谱进行了归属。在施加由点电荷产生的静电场时，考虑了周围蛋白质和氨基酸的影响。总体而言，我们的结果合理地再现了光合作用反应中心的光谱。我们发现蛋白质效应使一些吸收带向红区移动。接下来，我们计算了确定电子转移速率常数的电子转移积分。我们的结果重现了在光合作用反应中心观察到的L分支选择性。

Photosynthetic Reaction creates a large amount of energy on earth, which is basically of importance in the origin of life activity and of the human industrial activities. In this project, in order to clarify theoretically the photosynthetic reaction mechanism, we first studied the ground and excited states of various porphyrin compounds and of the socalled special pair which is in the photosynthetic reaction center, and then we studied the electron-transfer mechanism in the photosynthetic reaction center involving the effects of the surrounding proteins and aminoacids.First, we studied the ground and low-lying excited states of various porphyrin compounds including magnesium porphin, free base tetrazaporphin, free base phthalocyanine, oxyheme, carboxy-heme, horse radish peroxie CO,free-base Chlorin, free base bacteriochlorin, pheophytin and chlorophyll. The SAC-CI calculations accurately reproduced the spectra of these compounds. We presented some new theoreticallassignments, and explained the origin of the trends in these spectra. These results were important and necessary for the next step of our project.Next, we studied the excitation spectrum of the whole photosynthetic reaction center, and the electron transfer mechanism in the photosynthetic reaction center. We calculated all elements in the photosynthetic reaction center and assigned the spectrum theoretically. The effect of the surrounding proteins and aminoacids was considered applying the electrostatic field reproduced by the point charges. As a whole our result reasonably reproduced the spectrum of the photosynthetic reaction center. We found that the protein effect makes some absorption band shift to the red region. Next we calculated the electron transfer integrals which determine the electron transfer rate constants. Our results reproduced the L-branch selectivity observed in the photosynthetic reaction center.