Importance of a multiconfigurational description for molecular junctions

The importance of the multiconfigurational description of the junction electronic structure is investigated in quantum transport through molecular devices. Using an accurate wavefunction-based description of the low-energy spectroscopy, transport through a 2-electron/2-molecular orbital prototype is evaluated, covering lowly – H2-like – to highly – O2-like – correlated regimes. The contributions arising from the presence of competing singlet and triplet states in magnetic systems are analyzed. It is shown that the electronic conductivity provides a signature of the full multiplet energy spectrum, as well as of the multideterminant structure of wavefunctions.