A theoretical characterization of multiple isomers of the He 2I 2 complex

The present work has been directed at studying the structures and stabilization energetics of different conformers of the ground state He 2I 2 cluster. The full interaction between I 2 molecule and the He atoms is obtained from a sum-of-potentials scheme, using an analytical He-I 2 potential parametrized to ab initio calculations plus the He-He interaction. Quantum mechanical variational calculations are carried out, and binding energies as well as radial/angular probability density distributions are computed for the lower-lying vibrational van der Waals states. We found that they correspond to three different structural models, namely tetrahedral, linear and 'police-nightstick'. Comparison of these results with recent experimental data available from high-resolution spectroscopy for similar tetraatomic He 2-dihalogen complexes, contributes to evaluate their relative stability, and provides information about the importance of the multiple minima (global and local) of the potential surface used. © 2011 Elsevier B.V. All rights reserved.This work has been supported by DGICYT, Spain, Grant No. FIS2010-18132. P.B. acknowledges a postdoctoral fellowship from the Ramón Areces Foundation, Spain.Peer Reviewe