Time-dependent description of charge transport in molecular wires: bottom-up-approach

该项目的主要目标是开发一种新的全面的多尺度策略，用于线性分子导线中电荷输运的时间依赖性模拟。关于模拟技术，这些系统是非常具有挑战性的，因为电荷传输机制取决于链长。考虑到不同长度的有机线，绝热Landauer型相干隧穿和非绝热Marcus跳跃之间的实验输运制度已经得到证明。一个一致的理论应该有能力捕捉所有的过渡在运输制度取决于导线长度，热波动和环境影响。因此，量子动力学方法的基础上的粗粒度的描述的电子结构和治疗环境的影响，通过使用QM/MM技术以及稳态非平衡格林函数（NEGF）的运输计算在开放的边界条件下，将先进和适用于代表性的模型型系统。申请人已经在DFG优先计划SPP 1243的框架内介绍了基本方法。现在这些技术将迭代交叉连接和进一步发展，以消除现有的不足，并提高对整个Landauer-Marcus连续体的有机线输运计算的定量预测水平。具有以下特征的导线：它们应该是高技术相关性、实验可及性和可再现性的系统，可调长度代表不同的传输状态。为此，包括在该提议中的最相关的系统是低聚物，例如低聚（亚芳基亚乙炔基）和（OAE）、低聚（亚苯基亚乙炔基）衍生物（OPE）以及π-堆叠结构如DNA和螺旋肽，最近已经对其进行了电荷传输实验。目前的挑战是再现和量化不同运输制度之间的过渡，确定潜在的机制和调查可能的应用。

The major goal of the project is to develop a new comprehensive multi-scale strategy for time-dependent simulations of charge transport in linear molecular wires. Regarding simulation techniques these systems are highly challenging since charge transport mechanisms are depending on the chain length. Experimentally transport regimes between adiabatic Landauer-type coherent tunneling and non-adiabatic Marcus-hopping have been proven considering organic wires of varying lengths. A consistent theory should have the ability to capture all transitions in the transport regime depending on the wire length, thermal fluctuations and environmental effects. Therefore, quantum dynamical methods based on a coarse grained description of electronic structure and treating environmental effects by using QM/MM-techniques as well as steady state non-equilibrium Greens Functions (NEGF) transport calculations under open boundary conditions will be advanced and applied to representative model-type systems. The basic methods have been introduced by the applicants within the framework of the DFG Priority Program SPP 1243. Now these techniques will be iteratively cross-connected and developed further to remove existing deficiencies and improve the quantitative predictive level of transport calculations in organic wires towards the whole Landauer-Marcus continuum.The developed techniques will be applied to systems based on organic linear chains resp. wires with the following characteristics: they should be systems of high technological relevance, experimental accessibility and reproducibility, tunable length being representatives for different transport regimes. To this end, the most relevant systems to be included in this proposal are oligomers such as e.g. oligo(aryleneethynylene) and (OAE), oligo(phenylene ethynylene) derivatives (OPE) as well as pi-stacked structures like DNA and helical peptides on which recent charge transport experiments have been performed. The challenge is to reproduce and quantify transitions between different transport regimes, identify the underlying mechanisms and investigate possible applications.