Efficient algorithms for the simulation of the non-adiabatic exciton transfer dynamics in light-harvesting systems

捕光复合体捕获太阳光是生物系统光合作用的第一步。为了了解光合作用系统捕光复合体中结构和功能之间的微妙关系，必须通过计算机模拟来扩充实验数据，从而能够更详细地阐明这些复合体为实现有效的能量转换而使用的结构-功能关系和机制方面的图景。在过去的几年里，主要的理论进展为以更直接的方式计算激子转移过程开辟了道路。这涉及到发展快速和足够精确的半经验方法来描述基态和激发态的性质，并结合成多尺度的方法来处理包括其复杂的动力学效应在内的巨大系统。在这个方案中，我们想要将平衡的半经验量子化学与力场方法和非绝热传播方法相结合来计算电子的自由度，这将允许直接跟踪激子动力学。在这种组合的基础上，将计算实验观测数据以进行比较和验证。我们想要解决几个不同的系统，LH2，LH3，FMO和PC612复合体。到目前为止，这些系统已经进行了很好的实验研究，因此它们是理想的基准测试新方法，并展示了模拟如何增加洞察力，这是到目前为止还无法通过实验获得的。主要目标是开发一种可靠而又有效的方法，可以应用于其他生物和新的人工捕光复合体。

The capture of sunlight by light-harvesting complexes is the first step of photosynthesis in biological systems. In order to understand the subtle relationship between structure and function in light-harvesting complexes of photosynthetic systems, experimental data have to be augmented by computer simulations, which allow to elucidate a more detailed picture of the structure-function relationship and the mechanistic aspects of the processes used by these complexes for an efficient energy conversion. In the last years, major theoretical advances open the pathway for approaches to compute exciton transfer processes in a much more direct way. This concerns the development of fast and sufficiently accurate semi-empirical methods to describe the ground and excited states properties, combined into multi-scale approaches to address huge systems including their complex dynamical effects. In this proposal, we want to combine well balanced semi-empirical quantum chemistry with force field methods and non-adiabatic propagation approaches for the electronic degrees of freedom, which will allow to follow the exciton dynamics directly. Based on this combination, experimental observables will be computed for comparison and justification. We want to address several different systems, the LH2, LH3, FMO and PC612 complexes. Theses systems have been well studied experimentally so far, therefore they are ideal to benchmark out new approach and show, how simulation can add insights, which so far could not be gained experimentally. The major goal is to develop an reliable but yet efficient methodology, which can be applied to other biological and new artificial light-harvesting complexes.