Theoretical Study of the Reaction Mechanism of Low Energy Heavy Ion Collisions

1.研究了核内禀自由度对重离子聚变反应的影响。我们的主要结果是：（1）原子核的振动激发模大大提高了亚势垒能区的熔合截面。(2)这种增强主要是由于大的势能重整化。(3)<^（74）Ge>和<^（74）Ge>碰撞的异常大的增强表明在统一系统中诱导了<^（74）Ge>的大形变。(4)对于重系统，耦合通道方程的维数可以大大降低。(5)在绝热隧穿极限下，对聚变反应的几何解释成立.导出了低能重离子碰撞中由于核表面振动激发引起的能量和角动量耗散的延迟摩擦函数。阐明了耗散机制对入射能量的依赖性.导出了一个确定多维系统量子隧穿微观自由度滞后的公式。然后将该方法应用于μ子催化的d-t聚变，结果表明，单绝热性使μ子与聚变合成的α粒子的粘附概率降低了约30%.我们将Weidenmuller的新统计理论应用于核预平衡过程。结果在弱耦合极限下与Agassi等人的结果一致，但在强耦合极限下与Agassi等人的结果一致。并利用该方法计算了能级密度.我们使用含时平均场理论（TDMF）计算了弹性散射和吸收截面.我们表明，在<root>重离子反应的电子分析中的E约束来自于对激子数的约束。此外，我们计算了激子模型的能级密度，考虑到角动量。

1. We studied the effects of nuclear intrinsic degrees of freedom on the heavy ion fusion reactions. Our main results are: (1) Nuclear vibrational modes of excitation largely enhance the fusion cross section at sub-barrier energies. (2) This enhancement is mainly due to the large potential renormalization. (3) The extra-ordinarily large enhancement for the <^(74)Ge> and <^(74)Ge> collision suggests that a large deformation of <^(74)Ge> is induced in the unified system. (4) The dimension of the coupled-channels equations can be considerably reduced for heavy systems. (5) A geometrical interpretation holds for the fusion reaction in the limit of adiabatic tunneling.2. We derived the retarded friction functions for the energy and the angular momentum dissipation due to nuclear surface vibrational excitation in low energy heavy ion collisions. We then clarified the dependence of the dissipation mechanism on the incident energy.3. We derived a formula, which determines the lag of microscopic degrees of freedom in quantum tunneling in multi-dimensional systems. This method was then applied to the muon catalyzed d-t fusion, and showed that the mon-adiabaticity reduces the sticking probability of the muon to the fusion synthesized alpha particle by about 30 %.4. We applied Weidenmuller's new statistical theory to nuclear pre-equilibrium process. The result agreed with that of Agassi et al. in the limit of weak coupling, but differes in the strong coupling limit. Also, the level density was calculated by this method.5. We calculated the elastic scattering and the absorption cross sections using a time dependent mean field theory (TDMF).6. We showed that the <root> E constraint in the surprisal analysis of heavy ion reactions arises from a constraint to the exciton number. Also, we calculated the level density for the exciton model by taking into account the angular momentum.