STRUCTURE OF NEUTRON-DEFICIENT PT, HG, AND PB ISOTOPES

We study the shell closure properties of the even-even neutron-deficie nt Pt, Hg, and Pb isotopes using a deformed relativistic mean field fo rmalism. The ground state structures are investigated by comparing the prolate, oblate, and spherical solutions. Many of the nuclei are cons iderably deformed in their ground state configurations. Studies of the quadrupole and the hexadecapole moments, density distributions, and t he single-particle level structure clearly indicate that some of the n eutron-deficient isotopes having proton number Z = 82 do not behave as good magic nuclei.