Spectroscopic Properties of the Alkali–Krypton Diatomic M–Kr (M = Rb, Cs, and Fr) van der Waals Systems Including the Spin–Orbit Coupling

[Image: see text] Using an ab initio approach based on pseudopotential technique, pair potential approach, core polarization potentials, and large Gaussian basis sets, we investigate interaction of heavy alkali–krypton diatomic M–Kr (M = Rb, Cs, and Fr) van der Waals dimers. In this context, the core–core interactions for M(+)–Kr (M = Rb, Cs, and Fr) are calculated at coupled-cluster single and double excitation (CCSD) level and included in the total potential energy. Therefore, the potential energy curves are performed for 14 electronic states: eight of (2)Σ(+) symmetry, four of (2)Π symmetry, and two of (2)Δ symmetry. Furthermore, for each M–Kr dimer, the spin–orbit coupling has been considered for the B(2)Σ(+), A(2)Π, 3(2)Σ(+), 2(2)Π, 5(2)Σ(+), 3(2)Π, and 1(2)Δ states. In addition, the transition dipole moment has been determined, including the spin–orbit effect using the rotational matrix issued from the spin–orbit potential energy calculations.