Theoretical description of the electrical conduction in atomic and molecular junctions

We present a theoretical analysis of the electronic transport through atomic and molecular junctions. The main goal of this work is to show how the electronic structure of single atoms and molecules controls the macroscopic electrical properties of the circuits in which they are used as building blocks. In particular, we review our work on three basic problems that have received special experimental attention in recent years: (i) the conductance of a single-atom contact, (ii) the conductance of a hydrogen molecule and (iii) the current through single organic molecules.