Photoassociative Production and Trapping of Ultracold KRb Molecules

We have produced ultracold heteronuclear KRb molecules by the process of photoassociation in a two-species magneto-optical trap. Following decay of the photoassociated KRb*, the molecules are detected using two-photon ionization and time-of-flight mass spectroscopy of ${\mathrm{K}\mathrm{R}\mathrm{b}}^{+}$. A portion of the metastable triplet molecules thus formed are magnetically trapped. Photoassociative spectra down to $91{\mathrm{c}\mathrm{m}}^{-1}$ below the $\mathrm{K}(4s)+\mathrm{R}\mathrm{b}(5p_{1/2})$ asymptote have been obtained. We have made assignments to all eight of the attractive Hund's case (c) KRb* potential curves in this spectral region.