Ab initiocalculation 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 X¹Σ⁺ potential is found to be 0.30(2) ea₀ at the equilibrium internuclear separation with excess negative charge on the potassium atom. For the a³Σ⁺ potential the dipole moment is an order of smaller magnitude (1 ea₀=8.4783510^-30Cm). In addition, we calculate transition dipole moments between the two ground-state and excited-state potentials that dissociate to the K(4s)+Rb(5p) limits. Using this data we propose a way to produce singlet X¹Σ⁺ 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.