  An efficient method for computing the Landauer-Buettiker conductance of an
open quantum system within DFT+U is presented. The Hubbard potential is
included in electronic structure and transport calculations as a simple
renormalization of the non-local pseudopotential coefficients by restricting
the integration for the on-site occupations within the cutoff spheres of the
pseudopotential. We apply the methodology to the case of an Au monatomic chain
in presence of a CO molecule adsorbed on it. We show that the Hubbard U
correction removes the spurious magnetization in the pristine Au chain at the
equilibrium spacing, as well as the unphysical contribution of d electrons to
the conductance, resulting in a single (spin-degenerate) transmission channel
and a more realistic conductance of 1 G_0 . We find that the conductance
reduction due to CO adsorption is much larger for the atop site than for the
bridge site, so that the general picture of electron transport in stretched Au
chains given by the local density approximation remains valid at the
equilibrium Au-Au spacing within DFT+U.
