Structure of Mg31: Shape coexistence revealed by β-γ spectroscopy with spin-polarized Na31
Structure of Mg31: Shape coexistence revealed by β-γ spectroscopy with spin-polarized Na31
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Mg31 的结构：β-γ 能谱与自旋极化 Na31 揭示的形状共存
DOI：
10.1103/physrevc.99.024322
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发表时间：
2019
影响因子：
3.1
通讯作者：
Otsuka T.
中科院分区：
文献类型：
--
作者：
Nishibata H.;Kanaya S.;Shimoda T.;Odahara A.;Morimoto S.;Yagi A.;Kanaoka H.;Pearson M. R.;Levy C. D. P.;Kimura M.;Tsunoda N.;Otsuka T.
用自旋极化光谱学方法研究了位于核图=20“反转岛区”附近的能级结构。在中，形状共存预计是球面平均场和有利于形变组态的核关联之间微妙竞争的结果。在目前的工作中，我们利用自旋极化的各向异性衰变的独特方法使我们能够将所有正宇称激发能级的自旋牢牢地指定在2.3 MeV的中子分离能以下。此外，通过构造一个非常详细的衰变方案，包括两个新发现的能级，负宇称能级的自旋受到限制。对光谱信息的考察表明，具有和的变形转动带与在较高激发能区观察到的结构非常相似的转动带分别出现在In的基态和低激发态带中。实验水平的比较，在逐级的基础上，与两种类型的理论计算。第一种是反对称化分子动力学(AMD)加生成元坐标方法(GCM)，第二种是微观上由手征有效场理论导出的具有EEdf1相互作用的壳模型。据了解，在实验的11个能级中，有8个能级是四种大变形转动带的成员，2个能级是球形的。用4p4h组态的壳层模型计算成功地再现了2.244 MeV能级。本工作清楚地表明，各种结构共存于低激发能区。
The level structure of, which is located close to the region of the= 20 “island of inversion” in the nuclear chart, has been studied byspectroscopy with spin-polarized. In, shape coexistence is expected as a result of subtle competition between the spherical mean field and the nuclear correlation which favors deformed configurations. In the present work, our unique method utilizing the anisotropicdecay of spin-polarizedenables us to firmly assign the spins of all positive-parity excited levels inbelow the neutron separation energy at 2.3 MeV. Furthermore, by constructing a very detailed decay scheme, including two newly found levels, the spins of negative-parity levels are restricted. The examination of the spectroscopic information shows that the deformed rotational bands withand, which have very similar structures to those observed in a higher excitation energy region of, appear as the ground-state and low-lying bands, respectively, in. The experimental levels ofare compared, on the level-by-level basis, with two types of theoretical calculations. These are, first, the antisymmetrized molecular dynamics (AMD) plus generator coordinate method (GCM) and, second, the shell model with the EEdf1 interaction, which is microscopically derived from chiral effective field theory. It is understood that 8 levels among the experimental 11 levels are the members of four types of largely deformed rotational bands and 2 levels are of spherical nature. The2.244-MeV level is successfully reproduced by the shell-model calculation with a dominant 4p4h configuration. The present work clearly demonstrates that various structures coexist in a low excitation energy region of.