Characterization of van der Waals interaction potentialsD4h andTd configurations of He4

Van der Waals interaction potentials of the square planar D{sub 4h} and regular tetrahedral T{sub d} configurations of He{sub 4} were examined at the matrix Hartree-Fock, many-body perturbation theory, coupled-cluster theory, and configuration interaction levels of ab initio theory. Potential energy minima, pairwise and nonpairwise additivity, group theoretical parameters, and isotope substitution effects were found to uniquely characterize these interactions.