  We explore the quantum dynamics of heteronuclear atomic collisions in
waveguides and demonstrate the existence of a novel mechanism for the resonant
formation of polar molecules. The molecular formation probabilities can be
tuned by changing the trap frequencies characterizing the transverse modes of
the atomic species. The origin of this effect is the confinement-induced mixing
of the relative and center of mass motions in the atomic collision process
leading to a coupling of the diatomic continuum to center of mass excited
molecular states in closed transverse channels.
