Abstract :
We calculate energies E2+ and transition strengths B(E2)↑ of the lowest 2+ states of even Te, Sn and Ni isotopes in a neutron-rich region, using quasiparticle random phase approximation with simple separable type interactions. With those calculations reproducing the experimental systematics very well, we discuss, first, an unusual relation of E2+ and B(E2)↑ of 132, 136Te isotopes, which does not follow an empirical formula B(E2)↑∝1/E2+. Second, B(E2)↑ of 132Sn is discussed which is larger than those of the neighboring even Sn. This is a phenomenon confirmed by an experiment very recently. Third, we point out that the small B(E2)↑ of 68Ni is due to fragmentation of the transition strength into some excited states in a low-energy region.
