Dynamics of Di-Nuclear Systems

从双核分子的角度研究了在远高于库仑势垒的能量下的重离子散射中观察到的高自旋共振，如^<28>Si + ^<28>Si。通过计算弹性和非弹性通道的部分衰变宽度以及自旋排列，我们检验了“新分子模型”的可靠性，得到了长-长双核系统（^ Mg + ^Mg）在30 ~ 40 h高自旋下的稳定构型为极-极构型，扁<24><24>-扁双核系统（^ Mg + ^ Mg）为赤道-赤道构型<24><24>.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”模式移动时不接触，能量似乎高于蝴蝶能级。一般来说，蝴蝶激发态在互激发通道中表现出自旋矢量的反对齐，而反蝴蝶态则表现出对齐，这是由于相干振动运动的极点保持接触或不接触所致。这可以解释斯特拉斯堡数据中的不一致（^<28>Si+^<28>Si碎片角分布）。而在^<24>Mg + ^<24>Mg系统中，（2^+，2^+）通道中没有发现明显的位错，而在（4^+，2^+）通道中发现了明显的位错，这与实验结果相一致.最近对^<28>Si + ^<28>Si（斯特拉斯堡群）的粒子-粒子-γ测量显示出“m=0，垂直于反应面”的γ射线角分布.我们寻找了^ Si + ^ Si系统简正模中以“m=0”为主的组态<28><28>，发现在极高自旋下，由于三轴平衡组态（赤道-赤道组态）而产生的K-混合（倾斜模）。在反应过程中，赤道平行于平面，这就产生了平行于平面的自旋矢量，并显示出“m=0”的γ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.