Photoassociation as a probe of Feshbach resonances in cold-atom scattering

We investigate theoretically the influence of magnetically tunable Feshbach collision resonances on the photoassociation spectra of ultracold atoms. As an example we consider recently predicted resonances for ${}^{85}\mathrm{Rb}$ atoms. For excitation to the ${}^{85}{\mathrm{Rb}}_2{\mathrm{\hspace{0.5em}}0}_g^{-}{(S}_{1/2}{+P}_{1/2})$ electronic state, we predict that the photoassociation rate is resonantly enhanced by at least two orders of magnitude. We find that photoassociation could serve as a useful probe with which to study Feshbach resonances in ultracold collisions. In turn, these resonances should be very important to Bose-condensed gases, and more generally, to coherent atom optics.