  We report on the formation of ultra-cold Na$_2$ molecules using single-photon
photoassociation of a Bose-Einstein condensate. The photoassociation rate,
linewidth and light shift of the J=1, $v=135$ vibrational level of the
\mterm{A}{1}{+}{u} molecular bound state have been measured. We find that the
photoassociation rate constant increases linearly with intensity, even where it
is predicted that many-body effects might limit the rate. Our observations are
everywhere in good agreement with a two-body theory having no free parameters.
