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Energetics and Structures of Charged Helium Clusters: Comparing Stabilities of Dimer and Trimer Cationic Cores
Author(s) -
Marinetti Fabio,
Bodo Enrico,
Gianturco Franco A.,
Yurtsever Ersin
Publication year - 2008
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200800457
Subject(s) - trimer , ionic bonding , chemistry , chemical physics , energetics , dimer , ab initio , ion , atomic physics , ab initio quantum chemistry methods , helium , ionization , molecular physics , thermodynamics , molecule , physics , organic chemistry
We present accurate ab initio calculations of the most stable structures of He n + clusters in order to determine the more likely ionic core arrangements existing after reaching structural equilibrium of the clusters. Two potential energy surfaces are presented: one for the He 2 + and the other with the He 3 + linear ion, both interacting with one He atom. The two computed potentials are in turn employed within a classical structure optimization where the overall interaction forces are obtained within the sum‐of‐ potentials approximation described in the main text. Because of the presence of many‐body effects within the ionic core, we find that the arrangements with He 3 + as a core turn out to be energetically preferred, leading to the formation of He 3 + (He) n −3 stable aggregates. Nanoscopic considerations about the relative stability of clusters with the two different cores are shown to give us new information on the dynamical processes observed in the impact ionization experiments of pure helium clusters and the importance of pre‐equilibrium evaporation of the ionic dimers in the ionized clusters.