  The treatment of the previous paper is extended to molecular wires.
Specifically, the effect of electron-vibrational interactions on the electronic
transport induced by femtosecond $\omega+2\omega$ laser fields along unbiased
molecular nanojunctions is investigated. For this, the photoinduced vibronic
dynamics of trans-polyacetylene oligomers coupled to macroscopic metallic leads
is followed in a mean-field mixed quantum-classical approximation. A reduced
description of the dynamics is obtained by introducing projective lead-molecule
couplings and deriving an effective Schr\"odinger equation satisfied by the
orbitals in the molecular region. Two possible rectification mechanisms are
identified and investigated. The first one relies on near-resonance
photon-absorption and is shown to be fragile to the ultrafast electronic
decoherence processes introduced by the wire's vibrations. The second one
employs the dynamic Stark effect and is demonstrated to be highly efficient and
robust to electron-vibrational interactions.
