  We consider two-color heteronuclear photoassociation of atoms into dipolar
molecules in the J=1 electro-vibrational ground state, where a free-ground
laser couples atoms directly to the ground state and a free-bound laser couples
the atoms to an electronically-excited state. This problem raises an interest
because heteronuclear photoassociation from atoms to near-ground state
molecules is limited by the small size of the target state. Nevertheless, the
addition of the excited state creates a second pathway for creating ground
state molecules, leading to quantum interference between direct
photoassociation and photoassociation via the excited molecular state, as well
as a dispersive-like shift of the free-ground resonance position. Using LiNa as
an example, these results are shown to depend on the detuning and intensity of
the free-bound laser, as well as the semi-classical size of both molecular
states. Despite strong enhancement, coherent conversion to the LiNa
electro-vibrational ground state is possible only in a limited regime near the
free-bound resonance.
