We investigate the puzzling behavior [1,2] that for the neutron-rich 52-56Ti isotopes the fp-shell model calculations with recent effective interactions reproduce well the first excited 2+ energies, but are unable to describe the staggering of the B(E2;2+ ➝0+) values. We will report that this problem can be solved by introducing the g9/2 orbital into the fp-shell model space and the fpg shell model calculations [3] reproduce well the measured staggering pattern. It is clarified that the g9/2 orbital plays an important role for small B(E2) value in the Ti isotopes around the N=32.
It is also predicted that the excitations from the fp-shell to the g9/2 orbital provide the stronger binding energy corresponding to the larger deformation for the Ti isotopes around N=40. In this meeting, we demonstrate that the present calculations suggest a possible indication of a new island of inversion around the 62Ti, which is consistent with the recent experimental data of the enhanced cross sections [4].

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3. K. Kaneko, Y. Sun, M. Hasegawa, and T. Mizusaki, Phys. Rev. C 78, 064312 (2008).
4. O. B. Tarasov, et al., Phys. Rev. Lett. 102, 142501(2009).