New shell-model investigation of the lead-208 mass region: Spectroscopic properties and collectivity

Within the large-scale shell-model framework, an investigation of even-even nuclei in the vicinity of the Pb-208 closed core is reported in the present work. The calculations of the low-lying state energies and the electromagnetic transitions of the Pb, Po, Rn, Ra, and Th nuclei with 126 <= N <= 134 are performed using a new effective interaction H208 derived from CD-Bonn nucleon-nucleon potential, through the V-l(ow)-k procedure. A special focus is devoted to the degree of the collectivity, where a transitional region from spherical nuclear shape to weakly collective behavior is revealed.