  Coherent electronic transport through a molecular device is studied using
non-equilibrium Green's function (NEGF) formalism. Such device is made of a
short linear wire which is connected to para- and ferromagnetic electrodes.
Molecule itself is described with the help of Huckel (tight-binding) model with
the electron interactions treated within Hubbard approach, while the coupling
to the electrodes is modeled through the use of a broad-band theory. Coulomb
interactions within molecular wire are treated by means of the Hartree-Fock
(HF) approximation. For the case of asymmetric coupling to paramagnetic
electrodes, charging-induced rectification effect in biased molecular devices
is discussed as a consequence of Coulomb repulsion. For the system with
ferromagnetic electrodes, a significant magnetoresistance (MR) is predicted and
its oscillations generated by Coulomb interactions are considered.
