Theoretical study of the transition dipole moments and spin–orbit coupling and L-uncoupling functions of the LiCs molecule

Transition dipole moments as well as spin-orbit coupling and L-uncoupling matrix elements were evaluated for the LiCs molecule in a wide range of internuclear distances, <i>R</i>, for all electronic states converging to the first four dissociation limits. The asymptotic long-range behavior of the LiCs radial functions was investigated and compared with their counterparts obtained for the lighter LiNa, LiK and LiRb molecules. Electron correlation effects were accounted for in the framework of the configuration interaction (CI) method, where all sub-valence electrons were kept on doubly occupied orbitals and only two valence electrons remained free for explicit treatment. Semi-empirical core polarization potentials (CPPs) were used to account for the residual core-polarization effect. The Li atom was described using an all-electron aug-cc-pCVQZ basis set, while the Cs atom was described using a modified version of the averaged relativistic effective core potential (ECP). Along with the available potential energy curves, the current results can be useful in searching for the optimal optical cycle for laser assembling ultracold Li and Cs atoms by means of the STIRAP method as well as in performing a deperturbation analysis of both singlet and triplet state manifolds in the entire <i>R</i>-range.