Structure and anisotropy of ionic argon clusters using density functional models Original Research Article

Various density functional theory (DFr) approaches are examined in order to investigate their performance when describing the general behavior and the relative energetics of the potential energy surfaces (PES) of Arn+(X2Σ+) systems, with n = 2, 3 and 4. The selected modellings of correlation forces via DFr treatments show in the present example that the necessary contributions to interaction energies from such forces are rather well described in this way and compare well with conventional configuration interaction (Cl)calculations and with perturbative treatments with the same, or similar, initial basis set expansions. The present calculations further show the importance of correlation effects and of exact exchange contributions when modelling PES features of ionic rare gas systems.