New Aspects of Nuclear Deformation

核变形的新方面

基本信息

批准号：
06044249
负责人：
OTSUKA Takaharu
金额：
--
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Overseas Scientific Survey.
财政年份：
1994
资助国家：
日本
起止时间：
1994 至无数据
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06044249/
关键词：
Interacting Boson Model phonon rotational damping g-factor Pd Xe Cs Cs

项目摘要

In this research project, nuclear quadrupole and octupole deformations have been studied from various new aspects, including both dynamical and static deformations. The theoretical tool we have used is the Interacting Boson Model (IBM). The gamma-unstable deformation is known for Xe and Ba nuclei with the mass number -130, and is described by the O (6) limit of the IBM.The O (6) limit has been considered, in a classical term, as a gamma-unstable rotor. We, however, discovered an alternative picture where all eigenstates of the O (6) limit can be constructed as multiphonon states. This new approach is called the Q-phonon scheme. The phonons are excited on the top of a deformed equilibrium in this scheme. This scheme looks quite powerful in describing states even away from the O (6) limit. For instance, yrast odd-spin states can be described as Q-phonon states except for a singular point. The quantum chaos has been further studied in terms of the rotational damping and the width. We obtained a reasonable estimate of the width, and discussed branching numbers, etc. The octupole deformation has been studied with particular attention to the electric dipole transitions. The Interacting Boson-Fermion Model-2 has been used to analyze the g factors and M1 excitaion with respect to even-even Pd isotopes and odd-A rare-earth nuclei. Several odd-A Xe-Cs nuclei have been studied in terms of the Interacting Boson-Fermion Model-2, and a good agreement between experiment and calculation has been obtained.

在这个研究项目中，从各种新的角度研究了核四极和八极变形，包括动态和静态变形。我们使用的理论工具是相互作用玻色子模型（IBM）。质量数为 -130 的 Xe 和 Ba 核的伽马不稳定变形是已知的，并由 IBM 的 O (6) 极限描述。O (6) 极限在经典术语中被认为是伽马不稳定转子。然而，我们发现了另一种情况，其中 O (6) 极限的所有本征态都可以构造为多声子态。这种新方法称为 Q 声子方案。在此方案中，声子在变形平衡的顶部被激发。即使远离 O(6) 限制，该方案在描述状态方面看起来也相当强大。例如，除了奇点之外，yrast 奇自旋态可以描述为 Q 声子态。量子混沌在旋转阻尼和宽度方面得到了进一步研究。我们对宽度进行了合理的估计，并讨论了分支数等。对八极变形进行了研究，特别关注电偶极跃迁。相互作用玻色子-费米子模型 2 已用于分析偶偶 Pd 同位素和奇 A 稀土原子核的 g 因子和 M1 激发。利用相互作用玻色子-费米子模型2对几个奇数Xe-Cs核进行了研究，实验与计算得到了很好的吻合。