  We observe a light-induced frequency shift in single-photon photoassociative
spectra of magnetically trapped, quantum degenerate 7Li. The shift is a
manifestation of the coupling between the threshold continuum scattering states
and discrete bound levels in the excited-state molecular potential induced by
the photoassociation laser. The frequency shift is observed to be linear in the
laser intensity with a measured proportionality constant that is in good
agreement with theoretical predictions. The frequency shift has important
implications for a scheme to alter the interactions between atoms in a
Bose-Einstein condensate using photoassociation resonances.
