Phase equivalent potentials for three-body halos

We compare the properties of three-body systems obtained with two-body pote ntials with Pauli forbidden states and with the corresponding phase equival ent two-body potentials. In the first case the forbidden states are explici tly excluded in the calculation. Differences arise due to the off-shell pro perties of these on-shell equivalent potentials. We use the adiabatic hyper spherical method to formulate a practical prescription to exclude Pauli for bidden states in three-body calculations. Schematic as well as realistic po tentials are used. Almost indistinguishable results are obtained. (C) 1999 Elsevier Science B.V.