ANALYSES FOR MOLECULAR STRUCTURES IN HEAVY-ION RESONANCES BY USING PARTICLE-PARTICLE-GAMMA CORRELATIONS

对^<28>Si + ^<28>Si分子共振的粒子-粒子-伽马数据进行了分析。利用高自旋分子模型的r -矩阵散射振幅，理论上可以计算出共振衰变中发射的碎片^<28>Si的伽马射线强度。实验数据表明“rn = 0”，这意味着^<28>Si的自旋向量在反应平面上。我们研究了什么样的分子正常模式表现出这种特殊的核结构。以下机制已被期望获得平行于平面的自旋；1.^<28>Si + ^<28>Si的稳定构型预计为赤道-赤道接触构型，2。这种稳定构型具有三轴变形3。由于极高的自旋，旋转（J=38），整个变形的物体围绕最高转动惯量的轴旋转，这就产生了k -混合，即所谓的摆动模式。然后2 ^<28>Si的对称轴垂直于平面，自旋矢量在平面上，因为它们与坐标轴正交。这种旋转模式对于分子基态以及蝴蝶和反蝴蝶模式是可能的。我们也有另一种模式扭转，通过更简单的机制获得非对准，其中两个^<28>Si以相反的自旋矢量方向围绕分子轴旋转。向量平行于在反应平面上旋转的分子轴。将理论结果与实验数据进行比较，我们得出具有摆动旋转的分子基态是共振结构的候选者。另外两个不是很好的候选人，原因如下。在蝴蝶模式和扭曲模式下，自旋矢量分别平行于碎片方向和束方向。即使自旋平行于反应平面，我们也不会从过于集中的矢量中得到“m = 0”，因为“m = 0”需要“绕z轴对称”。

Particle-particle-gamma data from ^<28>Si + ^<28>Si molecular resonances was analised. By using R-matrix scattering amplitudes from high-spin molecular model, we can theoretically calculate gamma-ray intensities from the fragments ^<28>Si which are emitted from the resonance decays. The experimental data suggest "rn = 0" which, means the spins vectors of ^<28>Si are on the reaction plane. We studied what molecular normal modes exibits such a special nuclear structure.Following mechanism has been expected to obtain the spins parallel to the plane; 1.the stable configuration of ^<28>Si + ^<28>Si is expected to be an equator-equator touching configuration, 2.such a stable configuration has a tri-axial deformation, 3.due to extremely high spin, rotation(J=38), the total deformed object rotates around the axis of highest moments of inertia, which give rise to K-mixing so called wobbling mode. Then the symmetry axes of two ^<28>Si are perpendicular to the plane, and the spin vectors are on the plane because they are orthogonal to the axes. Such a rotational mode is possible for the molecular ground state and the butterfly and anti-butterfly modes. We have also another mode twisting to obtain non-alignments by simpler mechanism, in which two ^<28>Si spin around the molecular axis in the opposite spin-vector directions. The vectors are parallel to the molecular axis which rotates on the reaction plane.Comparing theoretical results with the data, we conclude that the molecular ground state with wobbling rotation is a candidate for the resonance structure. The other two are not good candidates by the following reason. In the butterfly mode and the twisting one the spin vectors are parallel to the fragment direction and the beam one, respectively. Even with the spins parallel to the reaction plane, we obtained no "m = 0" from too much concentrated vectors to own directions, because "m = 0" require "symmetry around z-axis".