Drip-line nucleus of Z=59 nuclei in the relativistic mean-field theory

The possible neutron and proton drip-line nuclei and their corresponding pr operties of Pr isotope chain are studied in the framework of the relativist ic mean-field (RMF) theory with non-linear meson self-interactions. The pai ring effect is treated by BCS method and the isospin dependent pairing stre ngths have been adopted. The 'blocking' method is used to deal with the las t unpaired nucleon and the axially symmetric deformation is assumed. The th eoretical results show that the nucleus Pr-185 could be determined as the l ast stable nucleus with respect to the nucleon emission on the neutron rich side from various aspects, while on the proton rich side,it is difficult t o determine the proton drip-line nucleus in present studies. The reason is that on the proton rich side the Fermi surface increases faster towards the continuum state than that on the neutron rich side, where the BCS method f ails,and the coupling between bound and continuum states should be taken in to account.