  We propose an improved photoassociation scheme to produce ultracold molecules
in their vibronic ground state for the generic case where non-adiabatic effects
facilitating transfer to deeply bound levels are absent. Formation of molecules
is achieved by short laser pulses in a Raman-like pump-dump process where an
additional near-infrared laser field couples the excited state to an auxiliary
state. The coupling due to the additional field effectively changes the shape
of the excited state potential and allows for efficient population transfer to
low-lying vibrational levels of the electronic ground state. Repetition of many
pump-dump sequences together with collisional relaxation allows for
accumulation of molecules in v=0.
