Theoretical studies of coherent energy transfer in photosynthetic systems

马萨诸塞州理工学院的Jianshu Cao获得了化学系化学理论，模型和计算方法项目的奖项，以计算研究光合作用中如何产生有效和稳健的相干能量转移，以及在光捕获系统中观察到的结构-功能关系如何帮助设计人工能源设备。当前项目所涉及的步骤将涉及（1）表征光捕获系统中的量子相干性，（2）使用随机波函数方法来现实地探索存在无序和噪声的时空相关性，以及（3）应用最优设计理论来最大化能量转移，从而探索供体-受体阵列中连接性和对称性的重要性。理解光合系统中能量传递的微观机制具有更大的意义，因为可以合理地预期协同蛋白质环境中的相干传递可能成为未来的普遍主题。除了为学生和博士后提供前沿培训外，这项工作还将纳入麻省理工学院的课程、麻省理工学院开放课程以及关于光合作用和基础能源科学的公开讲座。植物的光合作用始于含叶绿素的光合反应中心的蛋白质对光的吸收。 吸收的能量通过电子转移迅速转移到复杂蛋白质环境中的其他地方，以化学能的形式储存。 一个非常有趣的谜团是电子转移事件如何以这样一种方式发生，以避免在存储发生之前随机化能量。 这些超快事件越来越能够通过新的基于激光的实验来研究，但是通过经典的球和弹簧模型来模拟蛋白质不能再现协调的或连贯的能量转移。 相干性通常被认为需要用量子力学来描述，因此PI正在开发量子力学方法来理解光合作用中极其有效的能量转移的微观机制。 事实上，大自然已经找到了一种在复杂的蛋白质环境中建立这种合作的方法，这给我们带来了希望，我们可以在这个项目中探索，我们可以学会控制和优化能量转移效率，以应用于未来的人造光捕获设备。

Jianshu Cao of the Massachusetts Institute of Technology is supported by an award from the Chemical Theory, Models and Computational Methods program in the Chemistry Division to computationally investigate how efficient and robust coherent energy transfer arises in photosynthesis and how structure-function relations observed in light-harvesting systems can help the design of artificial energy devices. The steps involved in the current project will involve (1) characterizing quantum coherence in light-harvesting systems, (2) using the stochastic wave-function method to realistically explore spatial-temporal correlations in the presence of disorder and noise, and (3) applying optimal design theory to maximizing energy transfer and thus exploring the importance of connectivity and symmetry in donor-acceptor arrays. Understanding the microscopic mechanisms of energy transfer in photosynthetic systems is of larger significance since it is reasonable to expect that coherent transfer within collaborative protein environments may become a pervasive theme in the future. This work will, in addition to providing cutting-edge training for students and postdocs, be incorporated in the MIT curriculum, public-access MIT OpenCourseWare and public lectures on photosynthesis and basic energy sciences.Photosynthesis in plants starts with the absorption of light by proteins in chlorophyll-containing photosynthetic reaction centers. The absorbed energy is rapidly transferred elsewhere in the complex protein environment by transfer of electrons to be stored as chemical energy. A mystery of much interest is how the electron transfer events occur in such a way as to avoid randomizing the energy before storage occurs. These ultrafast events are increasingly able to be studied by new laser-based experiments, but modeling the proteins by classical ball-and-spring models cannot reproduce the coordinated, or coherent, energy transfer. Coherence is usually regarded as requiring a description by quantum mechanics, and the PI is therefore developing quantum mechanical approaches to understanding the microscopic mechanisms underlying extremely efficient energy transfer in photosynthesis. The fact that nature has found a way to establish this collaboration in complicated protein environments raises the hope, to be explored in this project, that we can learn to control and optimize energy transfer efficiency for application in future man-made light-harvesting devices.