Exotic Deformations at High Spin in Unsteble Nuclei

不稳定核中高自旋的奇异变形

基本信息

批准号：
08640368
负责人：
MATSUYANAGI Kenich
金额：
$ 0.83万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

1.To investigate possible occurrence of exotic deformations in proton-rich N<similar or equal>Z unstable unclei in the A=30-60 region, we have constructed a new powerful computer program for the Cranked Skyrme-Hartree-Fock calculations. The program is written in terms of the three-dimensional coordinate mesh representation without imposing any spatial symmetry restriction and use the imaginary time propagation technique. As the first application of this computer program, we have investigated high-spin states in ^<32>S and obtained the following theoretical predictions : 1)Appearance of an exotic rotational band possessing the Y_<31>-type deformation, in the region of the yrast line with angular momentum I=6-12, which simulataneously breaks the space-reflection and axial symmetries. 2)The superdeformed rotational band appear in the yrast line above I<similar or equal>14 and it shows an interesting internal structure change above I<similar or equa2.Classical periodic orbits responsible for emergence of the superdeformed shell structure for single-particle motions in spheroidal cavities have been identified and their relative contributions to the shell structures evaluted. Both prolate and oblate superdeformations as well as prolate hyperdeformations have been investigated. Fourier transform of quantum spectra clearly show that three-dimensional orbits born out of bifurcations of planar orbits in the equatorial plane become predominant at large prolate deformations while butterfly-shaped planar orbits bifurcated from linear orbits along the minor axis are important at large oblate deformations. Good correspondence between constant-action lines for these periodic orbits and valley structure in the oscillating part of the smoothed level density confirms the above conclusion.

1. 为了研究 A=30-60 区域中富质子 N<相似或相等>Z 不稳定叔克莱中可能发生的奇异变形，我们构建了一个新的强大的计算机程序，用于 Cranked Skyrme-Hartree-Fock 计算。该程序是根据三维坐标网格表示形式编写的，没有施加任何空间对称性限制，并使用虚数时间传播技术。作为该计算机程序的首次应用，我们研究了 ^<32>S 中的高自旋态，并获得了以下理论预测： 1）在该区域中出现了具有 Y_<31> 型变形的奇异旋转带角动量 I=6-12 的 yrast 线，同时打破了空间反射和轴对称。 2)超变形旋转带出现在I<相似或等于>14上方的yras线中，并且在I<相似或等于2以上显示出有趣的内部结构变化。经典周期轨道导致单粒子运动超变形壳结构的出现球状空腔中的空腔已被识别，并评估了它们对壳结构的相对贡献。长长形和扁形超变形以及长长形超变形都已被研究。量子光谱的傅里叶变换清楚地表明，在大扁长形变形中，由赤道平面中的平面轨道分叉产生的三维轨道变得占主导地位，而从沿短轴的线性轨道分叉的蝴蝶形平面轨道在大扁长形变形中很重要。这些周期轨道的恒定作用线与平滑能级密度振荡部分的谷结构之间良好的对应关系证实了上述结论。