The role of the intrinsic E2 matrix element between the first two 0+ states in their configuration mixing in 100Zr
The role of the intrinsic E2 matrix element between the first two 0+ states in their configuration mixing in 100Zr
复制标题
前两个 0 态之间的固有 E2 矩阵元素在 100Zr 中构型混合中的作用
DOI：
10.1016/s0370-2693(02)02219-0
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
D. Cline
中科院分区：
文献类型：
--
作者：
C. Wu;H. Hua;D. Cline
100Zr中的形状共存是一个众所周知的现象。然而，对于变形差异很大的两个形状之间的组态混合，还没有做出一致的描述。在这项工作中，从已知的带内跃迁和带间跃迁到基态带成员之间的γ-射线分支比，推算了100Zr中的B(E_2，2+2)值。后者的绝对尺度建立在这样的假设下，即旋转运动和本征运动之间的耦合对带间跃迁的调整可以用角动量依赖的微扰展开来近似。在描述中考虑了高达二阶的修正项，它解释了两个0+带之间的变形差异。假定转动关系，从B(E2，2+2≈0+2)值推导出331keV下第二个0+态的内禀E2矩阵元为→0.53EB。这表明弱形变的0+2态与〈01|E2|01〉≈1.06Eb的强形变基态共存。利用已知的E_0矩阵元和由此得到的内禀E_2矩阵元研究了两个0+态之间的组态混合。发现了≈7.7%的弱混合，比之前的分析建议的低了近两倍。从Yrast态的跃迁能系统学推导出的基态能量移动的定量证据与这种弱混合情形是一致的。本征E2矩阵元素分别为≈0.37Eb和≈1.14Eb的近球形和变形良好的形状分别被确定为混合发生前的基态。这两个未受扰动的0+态之间的内禀E2矩阵元≈0.19EB是描述它们组态混合所必需的。
Shape coexistence in100Zr is a well-known phenomenon. However, a consistent description of the configuration mixing between two shapes with very different deformation has not been made. In this work, the B(E2,2+2→0+2) value in100Zr has been inferred from the known γ-ray branching ratios between the intraband transition and the interband transitions to members of the ground-state band. The absolute scale of the latter was established under the assumption that adjustments to the interband transitions due to the coupling between the rotation and intrinsic motions can be approximated by a perturbation expansion of angular-momentum dependence. Correction terms up to the second order, which account for the deformation difference between two 0+bands, were considered in the description. The intrinsic E2 matrix elements for the second 0+state at 331 keV is derived to be ≈0.53 eb from the B(E2,2+2→0+2) value assuming a rotational relationship. This suggests that the weakly deformed 0+2state coexists with the strongly deformed ground state of 〈01|E2|01〉≈1.06 eb. Configuration mixing between the two 0+states has been studied using both the known E0 and the intrinsic E2 matrix elements derived from this work. A weak mixing of ≈7.7% was found, which is nearly a factor of two lower than suggested by a previous analysis. Quantitative evidence of the energy shift for the ground state, deduced from the systematics of transition energies for the yrast states, is consistent with this weak mixing scenario. Near-spherical and well-deformed shapes with the intrinsic E2 matrix elements of ≈0.37 eb and ≈1.14 eb, respectively, are identified as the basis states before the mixing takes place. The intrinsic E2 matrix element between those two unperturbed 0+states, ≈0.19 eb, is required to describe their configuration mixing.