Ab initio calculation of the KRb dipole moments

The relativistic configuration interaction valence-bond method has been used to calculate permanent and transition electric dipole moments of the KRb heteronuclear molecule as a function of internuclear separation. The permanent dipole moment of the ground-state X S potential is found to be 0.30~2! ea0 at the equilibrium internuclear separation with excess negative charge on the potassium atom. For the a S potential the dipole moment is an order of smaller magnitude ~1 ea058.47835 10 230 Cm). In addition, we calculate transition dipole moments between the two ground-state and excited-state potentials that dissociate to the K(4s) 1Rb(5p) limits. Using this data we propose a way to produce singlet X S KRb molecules by a two-photon Raman process starting from an ultracold mixture of doubly spin-polarized ground state K and Rb atoms. This Raman process is only allowed due to relativistic spin-orbit couplings and the absence of gerade-ungerade selection rules in heteronuclear dimers.