EAPSI: Probing Photosynthetic Processes with Computers

尽管在建造用于绿色能源生产的更高效和环境友好的太阳能机器方面取得了巨大进展，但设计既高效又便宜的太阳能电池仍然是一个挑战。这是研究在植物和细菌中发现的天然光合复合物的主要原因：这些生物体包含进化优化的结构，能够在将阳光转化为潜在可行能量方面产生接近100%的效率。由于许多关键的光合作用过程发生极快，有限的信息可以通过实验获得。这使得计算研究特别有用，并激励我们开发基于量子和经典物理的精确可靠的数学模型来模拟亚纳米和飞秒化学。与韩国浦项科技大学的Young Min Rhee博士合作，这项研究将联合收割机两种计算方法结合起来，开发出一种精确的方法来描述阳光如何在自然发生的光合复合物中转化为化学能。反应中心是光系统II色素蛋白复合物的一个亚基，在那里发生激子到电荷跃迁的多重量子跃迁。几个研究小组已经研究了这种复合物，但仍然不清楚为什么有些电荷转移态被创造出来，而另一些则没有。这项研究将集中在开发一个统一的模型的反应中心。蛋白质环境可以被视为激子流形的经典点电荷。然而，对于电荷分离的流形，带电的发色团将显著地干扰局部环境，并且静电荷描述将是不够的。因此，本研究将建立一个极化的代表性的蛋白质的QM/MM和MD计算。整体能量景观将被实施到量子动力学算法中，以模拟能量转移和转换。这个NSF EAPSI奖是与韩国国家研究基金会合作资助的。

Although great advances are being made to build more efficient and environment-friendly solar machines for green energy production, it still remains a challenge to design solar cells that are both efficient and inexpensive. This is the main reason to study naturally-occurring photosynthetic complexes found in plants and bacteria: these organisms contain evolutionarily optimized architecture capable of yielding near 100% efficiency in converting sunlight to potentially viable energy. Since many of the key photosynthetic processes occur extremely fast, limited information can be obtained experimentally. This makes computational studies especially useful and motivates our development of accurate and reliable mathematical models based on quantum and classical physics to simulate the sub-nanometer and femtosecond chemistry. In collaboration with Dr. Young Min Rhee at Pohang University of Science and Technology in Korea, this research will combine two computational methodologies to develop an accurate representation of how sunlight is converted to chemical energy in naturally occurring photosynthetic complexes.The reaction center is a subunit of the Photosystem II pigment-protein complex where exciton to charge-transition manifold quantum transition occurs. Several groups have studied this complex and yet, it still remains unclear why some charge-transfer states are created while others are not. This study will focus on developing a unifying model for the reaction center. The protein environment can be treated as classical point charges for the exciton manifold. However, for the charge-separated manifold, the charged chromophores will significantly polarize the local environment and a static charge description will not be sufficient. Thus, this study will build a polarizable representation of the protein for the QM/MM and MD calculations. The overall energy landscape will be implemented into quantum dynamics algorithm to simulate energy transfer and conversion. This NSF EAPSI award is funded in collaboration with the National Research Foundation of Korea.