Isomerism in the “south-east” of 132Sn and a predicted neutron-decaying isomer in 129Pd
Isomerism in the “south-east” of 132Sn and a predicted neutron-decaying isomer in 129Pd
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132Sn 的“东南-东”异构现象和 129Pd 中预测的中子衰变异构体
DOI：
10.1016/j.physletb.2016.09.030
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发表时间：
2016
影响因子：
4.4
通讯作者：
W. Zuo
中科院分区：
文献类型：
--
作者：
Cenxi Yuan;Zhong Liu;Furong Xu;P.M. Walker;Zs. Podolyák;C. Xu;Z.Z. Ren;B. Ding;M.L. Liu;X.Y. Liu;H.S. Xu;Y.H. Zhang;X.H. Zhou;W. Zuo
用壳模型计算方法研究了位于132 Sn东南方丰中子核的激发态。本文构造了一种新的壳模型哈密顿量。质子-质子和中子-中子相互作用的哈密顿量是通过现有的CD-Bonn G矩阵结果得到的，而质子-中子跨两个主要壳层的相互作用则是由基于π的普适相互作用加上M3 Y自旋轨道力得到的。该哈密顿量能很好地再现该区域的实验数据，包括单中子分离能、能级能和134，136，138 Sn，130 Cd和128 Pd的同分异构体的实验B（E2）值。在这一区域，如在135 Sn，131 Cd，129 Pd，132，134 In和130 Ag中预测了新的异构体，其中几乎没有实验已知的激发态。在奇-奇132，134 In和130 Ag中，讨论了预测的低位5−态的很长的E2寿命，需要更多有关质子-中子相互作用的信息。结合最近观测到的γ射线，讨论了132 In的低激发态。预测的129 Pd中的19/2−异构体可以通过电磁跃迁和中子发射衰变，具有相当的部分寿命，使其成为中子放射性的良好候选者，这是一种尚未发现的衰变模式。
Excited states in neutron-rich nuclei located south-east of 132 Sn are investigated by shell-model calculations. A new shell-model Hamiltonian is constructed for the present study. The proton–proton and neutron–neutron interactions of the Hamiltonian are obtained through the existing CD-Bonn G matrix results, while the proton–neutron interaction across two major shells is derived from the monopole based universal interaction plus the M3Y spin–orbit force. The present Hamiltonian can reproduce well the experimental data available in this region, including one-neutron separation energies, level energies and the experimental B (E 2) values of isomers in 134,136,138 Sn, 130 Cd, and 128 Pd. New isomers are predicted in this region, eg in 135 Sn, 131 Cd, 129 Pd, 132,134 In and 130 Ag, in which almost no excited states are known experimentally yet. In the odd–odd 132,134 In and 130 Ag, the predicted very long E2 life-times of the low-lying 5− states are discussed, demanding more information on the related proton–neutron interaction. The low-lying states of 132 In are discussed in connection with the recently observed γ rays. The predicted 19/2− isomer in 129 Pd could decay by both electromagnetic transitions and neutron emission with comparable partial life-times, making it a good candidate for neutron radioactivity, a decay mode which is yet to be discovered.