An approximate quantal treatment to obtain the energy levels of tetra-atomic X ⋅⋅⋅ I2 ⋅⋅⋅ Y van der Waals clusters (X,Y=He,Ne)

Abstract

The structure of tetra-atomic X ⋅⋅⋅ I2 ⋅⋅⋅ Y van der Waals (vdW) clusters, where X,Y=He,Ne, is studied using an approximate quantal treatment. In this model the above complexes are treated as like diatomic molecules with the rare-gas atoms playing the role of electrons in conventional diatomics. Then a H2-like molecular-orbital formalism is applied, choosing the discrete states of triatomic systems I2 ⋅⋅⋅ X(Y) as molecular orbitals. Calculations at fixed configurations as well as including vdW bending motions restricted to the plane perpendicular to the I2 axis have been carried out for the sake of comparison with previous results. Finally, the restrictions are relaxed and the vdW bending motions are incorporated in a full way within the framework of a configuration interaction. The structure of these clusters is also studied through the probability density function.