Theoretical study of spin-orbit and Coriolis coupling among the low-lying states of Rb2 and Cs2

•Spin-orbit and angular coupling matrix elements of Rb2 and Cs2 were ab initio calculated.•The predicted molecular parameters agree well with the most experimental counterparts.•Non-adiabatic treatment of Rb2 and Cs2 properties could be accomplished with high accuracy.

The spin-orbit (SO) and angular (Coriolis) coupling matrix elements of rubidium and cesium dimers have been calculated between the states converging to the lowest three dissociation limits. The relevant quasi-relativistic matrix elements were evaluated for a wide range of internuclear distances and density grid in the basis of the spin-averaged wave functions corresponding to pure Hund's coupling case (a). Both shape and energy consistent small (9-electrons) effective core pseudopotentials were used to monitor a sensitivity of the matrix elements to the particular basis set. The dynamic correlation has been taken accounted by a large scale multi-reference configuration interaction method which was applied for only two valence electrons. The l-independent core-polarization potentials were employed to take into account the residual core-valence effect. The assessment of current accuracy of the present ab initio functions is discussed by a comparison with preceding calculations and their empirical counterparts.

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