Zero-bias molecular electronics: Exchange-correlation corrections to Landauer's formula

We show that standard first principles calculations of transport through single molecules miss exchange-correlation corrections to the Landauer formula---the conductance is calculated at the Hartree level. Furthermore, the lack of derivative discontinuity in approximations can cause large errors for molecules weakly coupled to the electrodes. From the Kubo response theory, both the Landauer formula and these corrections in the limit of zero bias are derived and calculations are presented.