The goal of the proposed project is to achieve a better understanding of the way in which a specific molecular property manifests itself as a characteristic feature in transport experiments. We believe that such an understanding is scientifically rewarding and also an undispensable prerequisite for the development of a Molecular Electronics. The molecular peculiarities that we focus on are threefold. (1) We study the interplay between the spin transition, the molecular geometry and the Kondo effect in metal-organic compounds MeII(L)2. It is expected that in certain contact geometries the spin transition leads to a splitting, Δ, of the Kondo resonance. One goal is to quantitatively calculate Δ employing a combination of model calculations and correlated methods from quantum chemistry. (2) We investigate the electronic transport through physisorbed molecules, i.e. systems where the current flows through a van-der-Waals bond (“van der Waals barrier”). One particular focus is the C60-molecule that was recently proposed as a standard anchoring group in Molecular Electronics. (3) We use a rate equation approach to study light emission of a single molecule under a finite bias. All investigations, (1-3), have been motivated by recent findings in several experiments.
