Theoretical study of the Coriolis effect in LiNa, LiK, and LiRb molecules

Abstract

The non-adiabatic electronic matrix elements, L_ΠΣ(R), that arise from the spin-conserving electron-rotational interactions between all ^mΣ⁺ and ^mΠ states, where multiplicity m = 1, 3, converging to the lowest three dissociation limits of Li-containing alkali diatomics, LiM (M = Na, K, Rb), were calculated ab initio up to large internuclear distances, R. The required electronic wavefunctions were obtained within the framework of the multi-reference configuration interaction treatment of the two-valence-electron problem constructed using small-core scalar-relativistic effective core potentials and l-independent core-polarization potentials. A least squares analysis of the ab initio functions at large internuclear distances in conjunction with long-range perturbation theory (LRPT) revealed three different asymptotic behaviors of the L_ΠΣ(R → +∞)-functions: const. + β_[n]/Rⁿ, characterized by n = −1, 3 and 6. The asymptotic coefficients β_[n], extracted from the point-wise ab initio data, were found to be in agreement with their LRPT counterparts, which were evaluated analytically using the relevant atomic parameters. The mass dependence of the L_ΠΣ matrix elements was investigated analytically and numerically. To confirm the reliability of the L_ΠΣ(R)-functions and interatomic potentials at small and intermediate distances, the empirical q-factors available for the D¹Π-states of all LiM molecules studied were compared with their theoretical counterparts derived from the present ab initio data.