  Transport properties of asymmetric molecular structure are studied within the
kinetic equation approach, taking into consideration the electron interaction
in the self-consistent manner (SCF procedure). The device is made of a molecule
(modeled as a quantum dot with discrete energy levels) which is asymmetrically
coupled to the two metallic electrodes through the tunnel junctions. Electrical
rectification follows from the combined effect of the geometric asymmetry in
the molecular structure and simultaneously in the electrostatic potential
spatial profile. Primarily the influence of broadening and charging effects on
the charge and transport characteristics are investigated. Consequence of the
broadening is to smooth the charge-voltage (N-V) and current voltage (I-V)
functions, while the charging effect is rather responsible for the change of
the slope of both N-V and I-V curves. Inclusion of the electron-electron
repulsion results in significant enlargement of rectification ratio.
