Proposal For The Formation Of Ultracold Deeply Bound Rbsr Dipolar Molecules By All-Optical Methods

Ultracold paramagnetic and polar diatomic molecules are among the promising systems for quantum simulation of lattice-spin models. Unfortunately, their experimental observation is still challenging. Based on our recent ab initio calculations, we analyze the feasibility of all-optical schemes for the formation of ultracold Rb-87 Sr-84 bosonic molecules. A first possibility is photoassociation followed by spontaneous emission. The photoassociation rate coefficients toward electronic states converging to the Rb-87(5s( 2)S(1/2)) + Sr-84(5s5p P-3(0,1,2)) asymptotes are particularly small for vibrational levels close to the asymptote. The creation of molecules would be more interesting by using deeply bound levels which preferentially relax to the v '' = 0 level of the ground state. On the other hand, the photoassociation rate coefficients toward electronic states correlated to the Rb(5p P-2(1/2,3/2)) + Sr (5s(2) S-1(0)) are significant for levels close to the asymptote. The spontaneous emission thus creates weakly bound molecules in a single vibrational level. A second option relies on stimulated Raman adiabatic passage implemented in a tight optical trap. It efficiently creates weakly bound ground-state molecules in a well-defined level, thus providing a promising alternative to magnetic Feshbach resonances for further population transfer toward the absolute ground state of the RbSr molecule.