Importance of the three-body Pauli potential in three-cluster systems

The ground state energies of the 3α system and of theA-α-α system are calculated in the three-cluster fish bone optical model [1], It is found that the three-cluster Pauli potential is very strong in theM-version of the model and weak in the (off-shell transformed)¯M-version. Its influence on theΛ-α-α binding energy and ground state wave function is almost negligible in the¯M-version. The present results indicate that phenomenological three-cluster models with energy-independent two-cluster interactions are not necessarily in contradiction with more microscopic models. It seems to be important, however, to use potentials which contain in their off-shell behaviour both Pauli-principle and saturation character of the nuclear forces.