Bound-state energies in argon trimers via a variational expansion: The effects from many-body corrections

In this paper we study the bound-state energies and geometries of Ar3 for J=0, using the distributed Gaussian functions method that provides a configurational description of the different structures contributing to these states. Atom-atom potentials are employed and three-body long-range effects are also included in the computational treatment by adding to the sum of potentials the Axilrod-Teller triple-dipole correction for the whole rotationless energy spectrum. An estimate of the total number of bound states for the Ar trimer is given. With respect to previous calculations, limited to the lower-lying states, our results show slightly larger nonadditive effects and are further able to predict the full range of the bound spectrum. Changes on the geometries of a large part of the vibrationally excited states of Ar3 when the Axilrod-Teller term is included in the molecular potential are found by the present study. © 2005 American Institute of Physics.The nancial supports of the Ministry for University and Research sMUIRd, of the University of Rome I Research Committee, of the Italy-Spain Integrated Action Programme No. HI02-74, DGICYT Spanish Grant with Ref. FIS2004- 02461 and of the INFM institute, are gratefully acknowledged.Peer Reviewe