Ab initio investigation of molecular junctions with various stereoisomers and substituents

该项目建议研究分子连接，因为它们最近可以在断裂连接实验中获得。许多影响可能会控制通过这样一个结点的电流。考虑到它的纳米级，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，这是从最近发展的格林函数的量子化学方法得出的。该方法包括一个完整的从头计算方案，它放弃了建模和有效的参数化。它已被定制为一种灵活的分析工具，使其能够专注于据信至关重要的非常本地的过程。这里描述的项目致力于将这种方法应用于最紧迫的问题，即通过分子连接的电流如何受到各种影响的控制，从连接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。这对于进一步认识和发展单分子器件具有重要意义。因此，该项目在基础研究和纳米工程之间架起了一座桥梁。

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.