Stability and structure of singly-charged argon clusters Arn+, n = 3-27. A Monte Carlo simulation

Monte-Carlo calculations have been performed for positively charged argon clusters in the temperature range between 10K nd 40K using two different models (one with a dimer ion core, the other one with a trimer ion). The argon-argon interaction potential stems from empirical data, the ion-neutral atoms potential is determined by ab initio MRD-CI calculations. Special stability is found for clusters sizes n = 13, 19, 23 and 25/26 atoms using the 'trimeric core model' and for those with n = 14, n = 17, n = 20 using the 'dimetric core model'. The geometrical structure of the clusters is given and the construction principles are discussed in light of the interactions among neutral argon atoms and the ion-neutral atoms interaction. (orig.)