Analyzing and modeling the interaction potential of the ground-state beryllium dimer

The factors that caused the Be-2 potential to be quite different from other conventional van der Waals potentials are quantitatively delineated with relatively simple self-consistent-field calculations. By decomposing the potential into its three major components, we are able to show that the rather sudden change of slope in the potential energy curve around 3.2 angstrom is the result of the interplay between the sp hybridization and the correlation energy. It also enables us to model the interaction with a classical van der Waals potential, which provides the proper long-range behavior of the system, and a short-range attraction which mimics the effects of the sp hybridization.