Elementary Excitation Modes Built on Superdeformed High-Spin States

我们构造了一个计算机程序，可以求出建立在超形变高自旋态上的基本激发模的RPA方程的所有解。利用该程序，我们系统地研究了在超形变转动带上可能产生的等标量和等矢量型多极振动的性质。这项研究最重要的结论是理论上预测了轴比为2：1的超形变核相对于对称性为Y30、Y31和Y32的八极形变可能相当软。因此，提出了具有这种对称性的新型软振动模的存在，并讨论了利用下一代伽马射线探测器系统观测与之相关的电偶极跃迁的可能性。详细研究了这些新模式的微观结构以及它们随转动角动量的增加而发生的性质变化。

We have constructed a computer program that can find all solutions of the RPA equations for elementary excitation modes built on superdeformed high-spin states. Using this computer program, we have systematically investigated properties of multipole vibrations, both isoscalar and isovector types, which could be created on superdeformed rotation bands.The most important conclusion of this research is the theoretical prediction that the superdeformed nuclei with axis ratio 2 : 1 could be quite soft against the octupole deformations with the symmetry Y30, Y31 and Y32. Thus, existence of new types of soft vibrational modes having such symmetries are suggested, and the possibility of observing electric dipole transitions associated with them by means of the next generation of gamma-ray detector system has been discussed. The microscopic structure of these new modes and their change in character associated with the increase of the angular momentum of the rotational motion have been investigated in detail.