Ultracold collisions of spin-polarized SrF$(^2\Sigma^+)$ molecules with Rb($^2\mathrm{S}$) atoms in an external magnetic field*

Recent advances in molecular laser cooling have enabled the production of cold, trapped SrF$(^2\Sigma^+)$ and CaF$(^2\Sigma^+)$ radicals at sub-milliKelvin temperatures. To explore the feasibility of sympathetic cooling of SrF radicals using ultracold Rb atoms in a magnetic trap, we carry out accurate ab initio and quantum scattering calculations of ultracold Rb-SrF collisions. In spite of the significant anisotropy in the interaction potential between Rb and SrF, we find that fully converged scattering calculations on Rb-SrF collisions are possible using a total angular momentum basis including up to 125 rotational states of SrF and up to 3 total angular momentum blocks. We examine the sensitivity of the scattering cross sections to small variations of the interaction potential and use a statistical approach to estimate the success probability of atom-molecule sympathetic cooling.