Evolution of deformations in SD and PF shell nuclei

In the frame of deformed Skyrme Harlree-Fock (HF) model with pairing correlations, the strong mass number dependence of quadrupole deformations in sd and pf shell nuclei with mass A=(16 - 56) is studied as a clear manifestation of the evolution of nuclear deformation in nuclear many-body systems. The competition between the deformation driving particle-vibration coupling and the shell structure is shown by a systematic study on the ratios of the protons to neutrons quadrupole moments in nuclei with, T=|T_z| = 1. The mass number dependence of deformations obtained by deformed HF calculations is compared with the results of shell model and experimental data.