Shape transition observed in neutron-rich pf

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• 作者：N. Aoi ; H. Suzuki ; E. Takeshita ; S. Takeuchi ; S. Ota ; H. Baba ; S. Bishop ; T. Fukui ; Y. Hashimoto ; H.J. Ong ; E. Ideguchi ; K. Ieki ; N. Imai ; H. Iwasaki ; S. Kanno ; Y. Kondo ; T. Kubo ; K. Kurita ; K. Kusaka
• 关键词：Inverse scattering ; Fixed-energy and fixed incident direction scattering data
• 刊名：Nuclear Physics A
• 出版年：2008
• 出版时间：1 June 2008
• 年：2008
• 卷：805
• 期：1-4
• 页码：400-407
• 全文大小：754 K

文摘

The structure of the neutron rich pf-shell nuclei ⁵⁸Ti₃₆, ⁶⁰Cr₃₆ and ⁶²Cr₃₈ was studied by proton inelastic scattering in inverse kinematics. Large quadrupole deformation lengths of 1.12(16) fm and 1.36(14) fm were obtained for ⁶⁰Cr and ⁶²Cr, respectively, which confirm the enhanced collectivity in these nuclei. An excited state was observed in ⁶²Cr at 1180(10) keV with tentative assignment of J^π=4⁺. The increase in the E_x(4⁺)/E_x(2⁺) ratio indicates that the nature of collectivity changes from vibrational to rotational in ⁶²Cr and affords evidence for the development of static deformation. The excitation energy of the newly observed 2⁺ state in ⁵⁸Ti (1046(17) keV) shows hindered collectivity. The contrast between the structures of Cr and Ti suggests that the contributions of both protons and neutrons are crucial for the large collectivity in Cr close to N=40. From the comparison to shell model calculations, the large collectivity is found to originate from the admixture of the pf- and gd-shells across the N=40 sub-shell gap.