Dynamics of Di-Nuclear Systems

在远高于库仑势垒的重离子散射中，如^<28>Si + ^<28>Si，已经从双核分子的角度进行了高自旋共振的研究。我们通过计算弹性和非弹性通道和自旋排列的部分衰减宽度来检验“新分子模型”的可靠性。在高自旋3040h下，我们已经获得了长-长双核系统的极-极稳定构型（^<24>Mg + ^<24>Mg）和扁圆-扁圆系统的赤道-赤道稳定构型（^<24>Mg + ^<24>Mg）。在这些平衡点周围，发现了各种振动模式：“蝴蝶”模式保持极对极接触，能量较低，而“反蝴蝶”模式不接触而运动，能量高于蝴蝶水平。一般来说，蝴蝶激发态在互激通道中表现出自旋矢量的反对准，而反蝴蝶态则表现出对齐，这是由于相干振动运动极点保持接触或不保持接触。可以解释斯特拉斯堡数据（^<28>Si+^<28>Si碎片角分布）中的衰减。相反，在^<24>Mg + ^<24>Mg体系中，在（2^+,2^+）通道中没有发现明显的失调，但在（4^+,2^+）通道中发现了明显的失调，这似乎与实验一致。最近在^<28>Si + ^<28>Si（斯特拉斯堡群）中的粒子-粒子-伽马测量显示出“m=0，垂直于反应面”的伽马射线角分布。我们在^<28>Si + ^<28>Si体系的正态模式中寻找了“m=0”占主导地位的构型，并在极高的自旋下发现了由于三轴平衡构型（赤道-赤道构型）导致的k -混合（倾斜模式），在反应过程中，赤道平行于平面，这使得自旋矢量平行于平面，并显示出“m=0”的伽马射线分布。

High spin resonances observed in the heavy-ion scattering at energies far above the Coulomb barriers, such as ^<28>Si + ^<28>Si have been studies from viewpoints of di-nuclear molecules. We have examined the reliability of "new molecular model" by calculating partial decay widths to the elastic and inelastic channels and spin alignments.We have obtained stable configurations to be pole-to-pole ones for prolate-prolate dinuclear systems (^<24>Mg + ^<24>Mg), and equator-to-equator ones for oblate-oblate systems (^<24>Mg + ^<24>Mg), at high spins of 30 40h. Around those equilibria, various vibrational modes have been found : "butterfly" mode keeps pole-to-pole touching and appears lower in energy, while "anti-butterfly" moves without touching and appears higher than the butterfly levels. Generally butterfly excited states show anti-alignments of spin vectors in the mutual excitation channels, and anti-butterfly states show alignments, due to the coherent vibrational motions poles keeping in touch or not. It is possible to explain disalinments in the Strasbourg data (^<28>Si+^<28>Si fragments angular distributions). In contrast, in the ^<24>Mg + ^<24>Mg system clear disalignments have not found in the (2^+, 2^+) channel, but found in the (4^+, 2^+) channel, which seems to be in agreement with experiments.Recent particle-partile-gamma measurements in ^<28>Si + ^<28>Si (Strasbourg group) have exhibited "m=0 in normal to the reaction plane" gamma-ray angular distributions. We have searched for the configurations with "m=0" dominance in the normal modes for ^<28>Si + ^<28>Si system, and found K-mixing (tilting mode) due to triaxial equilibrium configurations (equator-equator ones) in extremely high spins, In the reaction course, equators are parallel to the plane, which gives spin vectors parallel to the plane and shows "m=0" gamma-ray distributions.