Partitioning technique and transport across molecular interfaces: Many-body effects

We review the theory of transport across molecular interfaces within the framework of the partitioning and inner projection techniques, developed by Per-Olov Löwdin. Using a one-particle approximation to the many-body equation for the current in a system consisting of a molecular bridge and two electrodes, it is shown that the idea of partitioning can be used advantageously to define a self-energy that contains the coupling of the molecule to the electrodes. Inner projections are then introduced as a systematic way of including electron correlation effects in the transport across molecular junctions.