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EFFECTS OF NON-ADLABATIC TRANSITION ON NUCLEAR DYNAMICAL PROCESSES

非绝热转变对核动力学过程的影响

基本信息

批准号：
08640380
负责人：
TAZAWA Terutake
金额：
$ 1.54万
依托单位：
YAMAGUCHI UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

(1) Analytical formulae for the S-matrix are derived for a two-state curve crossing problem in the presence of potential barriers by using a three turning point semiclassical theory and a matrix formalism for the non-adiabatic transition. They satisfy the unitarity condition and the elasitc and inelasitc S-matrix elements reduce to improved Landau-Zener-Stuckelberg formulae at high energies where the existence of the potential barrier can be ignored. We discuss qualitative behaviors of the semiclassical S-matrix elements in the weak and strong coupling limits, i.e. in the limits where the one-way Landau-Zener transition probability p* 1 and p * 0, respectively. We also discuss the possible interplay between the Landau Zener transtion and the potential resonance. In such a system as ^<13>C + ^<17>O, we show that the inelastic partial cross section attributed to the Landau-Zener transition is strongly enhanced by the potential resonance in case that the avoided crossing exists inside the … More Coulomb barrier. We also show the inelastic partial cross section is strongly suppressed by the destructive interference between the phase accompanied with the Landau-Zener transition and the phase-shifts for the adiabatic potential scattering when the avoided crossing exists outside the Coulomb barrier.(2) The roles of higher order coupling of sufface vibrations and anharmonicites, the possibilities of extracting the sign of the deformation, effects of adiabatic quantum tunneling and of finite width of excited states are investigated by the theoretical aanlyses of the several kinds of experimental data in heavy-ion fusion reactions at near and below the Coulomb barrier. We predicted such a new mechanism as grory in the shadow of rainbow in heavy-ion scattering. It is also shown that the bombarding energy-dependence of the cross section at very small angle is effective to identify it.(3) Shielding effect of the electrons bounded in the target nuclei on nuclear fusion reactions at very low energies is now investigated. The numerical calculation is now in progress in the case of d + D system by using the dynamical norm method and non-adiabatic potential method equivalent to that.(4) The collision between a cluster and a highly charged ion, and subsequent production of the highly charged cluster, are investigated in the time-dependent local-density approximation. The multiple electron transfer passing over the saddle of the potential barrier is predicted and is in good agreement with an estimate by the simple classical overbarrier model. A microscopic calculation of the collision between highly charged ion and rare gas atom in the same approximation has been carried out. The calculated charge transfer cross sections are in fair agreement with measurements, the semi-classical formula and the molecular classical overbarrer model. Less

(1)利用三拐点半经典理论和非绝热过渡的矩阵形式，导出了存在势垒时两态曲线交叉问题的s矩阵解析表达式。它们满足统一条件，弹性和非弹性s -矩阵元在高能量下简化为改进的Landau-Zener-Stuckelberg公式，在高能量下可以忽略势垒的存在。讨论了半经典s矩阵元在弱耦合极限和强耦合极限下的定性行为，即单向朗道-齐纳跃迁概率分别为p* 1和p* 0的极限。我们还讨论了朗道-齐纳跃迁与势共振之间可能的相互作用。在^<13>C + ^<17>O这样的体系中，当避免的交叉存在于…More库仑势垒内时，势共振强烈地增强了归因于朗道-齐纳跃迁的非弹性部分截面。我们还发现，当避免交叉存在于库仑势垒外时，非弹性部分横截面被伴有朗道-齐纳跃迁的相与绝热势散射的相移之间的干涉所强烈抑制。(2)通过对库仑势垒附近和库仑势垒以下几种重离子聚变反应实验数据的理论分析，探讨了表面振动和非调和子高阶耦合的作用、变形符号提取的可能性、绝热量子隧穿效应和激发态有限宽度的影响。在重离子散射中，我们预测了彩虹阴影中的灰色等新机制。研究还表明，利用极小角横截面的轰击能量依赖关系可以有效地对其进行识别。(3)研究了目标原子核中束缚电子对极低能量核聚变反应的屏蔽效应。采用动力范数法和等效的非绝热势法对d + d系统进行了数值计算。(4)在时间相关的局部密度近似中，研究了团簇与高电荷离子之间的碰撞以及随后产生的高电荷团簇。预测了通过势垒鞍的多重电子转移，并与简单的经典过势垒模型的估计相吻合。本文对高电荷离子与稀有气体原子在相同近似下的碰撞进行了微观计算。计算的电荷转移截面与测量值、半经典公式和分子经典过障模型基本一致。少