Phenomenological description of non-axial shapes of some doubly even neutron deficient barium isotopes

The evolution of non-axial shapes and rotational structure in even–even ^122–132Ba isotopes has been investigated microscopically with the application of a triaxial projected shell model (TPSM). Based on calculations, the shape instability and softness towards γ deformation are predicted for these isotopes. In the present work, the application of three-dimensional angular-momentum projection on multi-quasiparticle configurations, constructed from the triaxially deformed mean field, provides a reliable description of the yrast and near yrast structure in these nuclei. The theoretically obtained backbends demonstrate the importance of decoupling of multi-quasiparticle states for these nuclei. The uniform behaviour of transition probabilities B(E $2_1^{+}\to 0_1^{+}$), shown by the present calculations, authenticate the global validity of Grodzin's product rule. Besides this, the deformation systematics and odd–even staggering in γ bands have also been discussed in the present work. (paper)