Ab initio calculations for Ar-2(+), He-2(+), of interest for the modelling of ionic rare-gas clusters

Large CI ab initio calculations are performed for Ar-2(+), He-2(+) and He-3(+). For both ionic dimers a complete set of accurate data is determined, including the various electronic states and the transition moments to be used for spectroscopical studies and for modelling larger ionic rare-gas clusters; Spectroscopic constants for Ar-2(+) are in remarkable agreement with the experimental results. The study for He-3(+) confirms the failure of the minimal DIM model for helium ions.