TOWARDS RELIABLE MODELING OF LARGE CLUSTERS - ON THE OVERALL ACCURACY OF THE DIATOMICS-IN-MOLECULE METHOD FOR RARE-GAS CLUSTER IONS

The accuracy of the diatomics-in-molecules (DIM) method is examined for the case of rare gas ionic clusters through a series of careful calibration calculations. Ab initio potential energy functions for Rg(3)(+) and Rg(4)(+) (Rg = He, Ne, Ar) are 3 compared with the DIM model, taking diatomic potentials computed at exactly the same level of ab initio theory as input. For Ne-n(+) and Ar-n(+) agreement is satisfactory (in most important regions within 0.05 eV), whereas for He-n(+), large deviations occur.