3-BODY CONFIGURATION-SPACE CALCULATIONS WITH HARD-CORE POTENTIALS

We present a mathematically rigorous method suitable for solving three -body bound-state and scattering problems when the inter-particle inte raction is of a hard-core nature. The proposed method is a variant of the boundary condition model and it has been employed to calculate the binding energies for a system consisting of three He-4 atoms. Two rea listic He-He interactions of Aziz and collaborators have been used for this purpose. The results obtained compare favourably with those prev iously obtained by other methods. We further used the model to calcula te, for the first time, the ultralow-energy scattering phase shifts. T his study revealed that our method is ideally suited for three-body mo lecular calculations where the practically hard-core of the inter-atom ic potential gives rise to strong numerical inaccuracies that make cal culations for these molecules cumbersome.