  We show that coherence between two excited ro-vibrational states belonging to
the same molecular electronic configuration arises quite naturally due to their
interaction with electromagnetic vacuum. For initial preparation of a molecule
in the desired ro-vibrational states, we propose to employ the method of
ultracold photoassociation. Spontaneous decay of the excited molecule then
gives rise to vacuum induced coherence between the excited ro-vibrational
states. We demonstrate theoretically an interesting interplay of effects due to
vacuum induced coherence and photoassociation. We apply our theory to
photoassociation of bosonic Ytterbium (^{174}Yb) atoms which appear to be a
promising system for exploring such interplay. The effects discussed here can
be important for controlling decoherence and dissipation in molecular systems.
