Evidence for reduced collectivity around the neutron mid-shell in the stable even-mass Sn isotopes from new lifetime measurements

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• 作者：A. Jungclaus ; J. Walker ; J. Leske ; K.-H. Speidel ; A.E. Stuchbery ; M. East ; P. Boutachkov ; J. Cederkä ; ll ; P. Doornenbal ; J.L. Egido ; A. Ekströ ; m ; J. Gerl ; R. Gernhä ; user ; N. Goel ; M. Gó
• 关键词：Lifetimes ; Sn isotopes ; Doppler shift attenuation technique
• 刊名：Physics Letters B
• 出版年：2011
• 出版时间：10 January 2011
• 年：2011
• 卷：695
• 期：1-4
• 页码：110-114
• 全文大小：220 K

文摘

Precise measurements of the lifetimes of the first excited 2⁺ states in the stable even-A Sn isotopes ^112–124Sn have been performed using the Doppler shift attenuation technique. For the isotopes ¹¹²Sn, ¹¹⁴Sn and ¹¹⁶Sn the E2 transition strengths deduced from the measured lifetimes are in disagreement with the previously reported values and indicate a shallow minimum at N=66. The observed deviation from a maximum at mid-shell is attributed to the obstructive effect of the s_1/2 neutron orbital in generating collectivity when near the Fermi level.