  The representation of the potential energy surfaces of atom molecule or
molecular dimers interactions should account faithfully for the symmetry
properties of the systems, preserving at the same time a compact analytical
form. To this aim, the choice of a proper set of coordinates is a necessary
precondition. Here we illustrate a description in terms of hyperspherical
coordinates and the expansion of the intermolecular interaction energy in terms
of hypersherical harmonics, as a general method for building potential energy
surfaces suitable for molecular dynamics simulations of van der Waals
aggregates. Examples for the prototypical case diatomic molecule diatomic
molecule interactions are shown.
