项目旨在通过QM/MM计算和QM/MM-based MD模拟，结合光诱导电子转移动力学理论研究，探索光系统II光催化水氧化的分子机制及其电子转移耦合质子转移的性质。重点开展几类重要色素分子（叶绿素a、去镁叶绿素a等）在光系统II蛋白质环境中激发态性质和光诱导电子转移过程的理论研究，锰簇(Mn4O5Ca)不同氧化还原态(Si, i=0-4)几何结构和电子结构的QM/MM计算表征。探明光诱导色素激发态分子内电子转移、分子间电子转移和O-O键形成的微观机理，预测光系统II反应中心蛋白质环境、介质、配体对其光催化活性和光物理与光化学性质的影响，为完全了解光合作用的机理研究和拓展人工光合作用的应用提供理论支持。

The project aims to explore plausible mechanisms of the photosynthetic water oxidation and the electron-coupled proton transfer in photosystem II by QM/MM calculations and QM/MM-based MD simulations, in combination with the theoretical investigation on the photo-induced electron transfer dynamics. Our calculations and simulations will focus on the excited states of several types of important pigment molecules (chlorophyll a, pheophytin a, etc.) and their energy and electron transfer processes in the protein environment of photosystems II, as well as computational characterization of the catalytic Mn4O5Ca cluster at different oxidation states (Si, i = 0-4). Based on extensive calculations, we try to understand the oxygen-evolving complex (OEC) function of photosystem II containing a Mn4O5Ca catalytic site at the atomic and molecular levels and the effects of protein environments, media, ligands around the reaction center on its photocatalytic reactivity, and provide a theoretical basis for fully understanding the photosynthesis mechanism and accelerating the application of artificial photosynthesis.