Evolution of deformations in medium-mass nuclei

Evolution of quadrupole deformations in sd- and pf-shell nuclei with mass A=18~56 is studied by using deformed Skyrme Hartree-Fock model with pairing correlations. We point out that the quadrupole deformations of the nuclei with the isospin T=0 and T=1 show strong mass number dependence as a clear manifestation of dynamical evolution of deformation in nuclear many-body systems. The competition between the deformation driving particle-vibration coupling and the closed-shell structure is shown in a systematic study of the ratios between the proton and neutron deformations in nuclei with T=|Tz|=1. Calculated quadrupole and hexadecapole deformations are compared with shell model results and available experimental data. A relation between the skin thickness and the intrinsic Q2 moments is also discussed.