Ab initio investigation of molecular junctions with various stereoisomers and substituents

该项目建议研究分子结，因为它们最近可以在断裂结实验中获得。许多影响可能控制通过这样一个结的电流。鉴于其纳米尺度，理论研究必须基于量子力学方法。在这个项目中，我们分析了分子结的传输特性，这些特性来自于最近发展的绿色函数的量子化学方法。该方法包括一个完整的从头算方案，放弃建模和有效的参数化。它已被定制成一个灵活的分析工具，使重点放在非常当地的过程被认为是必不可少的。这里描述的项目致力于将这种方法应用于最紧迫的问题，即通过分子结的电流如何受到各种影响的控制，这些影响从结的几何排列到分子形状的特殊变化（立体异构化）到化学取代。这些对于进一步理解和发展单分子器件具有重要意义。因此，该项目弥合了从基础研究到纳米工程的差距。

The project suggests to investigate molecular junctions as they can be recently obtained in break-junction experiments. Many influences might control the electric current through such a junction. Given its nanoscale, theoretical investigations must be based on quantum mechanical methods. In this project we analyze the transmission properties of molecular junctions as derived from a recently developed quantum chemical approach to the Green's function. The method consists of a full ab initio scheme which renounces modelling and effective parametrization. It has been tailored into a flexible analytic tool which allows to focus on the very local processes believed to be essential. The project described here strives to apply this approach to the most urgent questions of how the electric current through a molecular junction might be controlled by various influences reaching from the very geometric arrangement of the junction via particular changes in the shape of the molecule (stereoisomerization) to chemical substitution. All these points are of paramount importance for the further understanding and development of single molecule devices. The project thus bridges a gap from fundamental research to nano engineering.