Production of heteronuclear molecules in an electronically excited state by photoassociation in a mixture of ultracold Yb and Rb

We have produced ultracold heteronuclear YbRb* molecules in a combined magneto-optical trap by photoassociation. The formation of electronically excited molecules close to the dissociation limit was observed by the trap loss spectroscopy in mixtures of Rb-87 with Yb-174 and Yb-176. The molecules could be prepared in well-defined rovibrational levels, allowing for an experimental determination of the long-range potential in the electronically excited state.