Shell Evolution and E2 Collectivity: New Spectroscopic Information

New spectroscopic information on electric quadrupole collectivity has recently been obtained. We report on our identification of a coexisting deformed structure in the quasi-doubly closed-shell nucleus 96Zr from our measurement of a corresponding absolute E2 intraband transition strength in electron scattering reactions and its small mixing matrix element with the spherical ground state structure. The even-mass zirconium isotopes exhibit a first order quantum shape phase transition between neutron numbers 58 and 60. We have used photon scattering reactions for a first measurement of the E2 decay strength of the nuclear 1+ scissors mode. Evidence for its 2+ rotational excitation and its extraordinarily large rotational moment of inertia are presented.

Structure of the Super Neutronised Doubly Closed Shell Nucleus 132Sn

The scenario of single particle (proton as well as neutron) states near the Fermi surface of 132Sn has been investigated on the basis of an average one-body potential suitably optimised for 208Pb and then extrapolated to the mass region concerned. The calculation shows excellent agreement with experiment. The ground state charge distribution of the nucleus has also been calculated.