The ground state van der Waals potentials of the calcium dimer and calcium rare-gas complexes

The entire potential energy curve of the Ca-2 ground state generated by the Tang-Toennies potential model with its parameters specified by the three theoretical dispersion coefficients and the experimentally determined equilibrium distance and well depth is in excellent agreement with the accurate experimental potential of Allard et al. [Phys. Rev. A 66, 042503 (2002)]. The reduced potential of Ca-2 is almost identical with that of Hg-2. This leads to the conjecture that the ground state van der Waals dimer potentials of group IIA, except Be, and group IIB elements have the same shape, which is different from that of the rare-gas dimers. The potentials of Ca-RG complexes (RG=He, Ne, Ar, Kr, Xe) are generated by the same potential model with its parameters calculated from the homonuclear potentials of calcium and rare-gas dimers with combining rules. The predicted spectroscopic constants are comparable to other theoretical computations. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3246351]