Theoretical study of the bonding in M(n+)-RG complexes and the transport of M(n+) through rare gas (M=Ca, Sr, and Ra; n=1 and 2; and RG=He-Rn)

We present high level ab initio potential energy curves for the M(n+)-RG complexes, where n=1 and 2; RG=He-Rn; and M=Ca, Sr, and Ra. Spectroscopic constants have been derived from these potentials and are compared with a wide range of experimental and previous theoretical data, and good agreement is generally seen. Large changes in binding energy, D(e), and bond length, R(e), between M(+)-He, M(+)-Ne, and M(+)-Ar, also found previously in the analogous Ba(+)-RG complexes [M. F. McGuirk et al., J. Chem. Phys. 130, 194305 (2009)], are identified and the cause investigated; the results shed light on the previous Ba(+)-RG results. These unusual trends are not observed for the dicationic complexes, which behave in a fashion similar to the isoelectronic alkali metal ion complexes. The potentials have also been employed to calculate transport coefficients for M(n+) moving through a bath of rare gas (RG) atoms.