Towards reliable modelling of large clusters: on the overall accuracy of the diatomics-in-molecule method for rare gas cluster ions

Abstract

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 Rg3+ and Rg4+ (RgHe, Ne, Ar) are compared with the DIM model, taking diatomic potentials computed at exactly the same level of ab initio theory as input. For Nen+, agreement is satisfactory (in most important regions within 0.05 eV), whereas for Hen+, large deviations occur.