The true potentiaI energy curves have been constructed for the different electronic states of Pz + molecule by the method of La~lcshm.an and Rao. The dissociation energy for the ground state of the P+ molecule has been estimated to be 4.03 eV by the method of curve fitting using the three-parameter Lippincott potential function. The ionisation potential of P~ molecule has been estimated as 11.98 eV which is in good agreement with the value given by Gaydon.