Landau-Zener Effects in Nuclear Heavy-Ion Reactions

1.研究了核重离子碰撞中的Landau-Zener能级交叉是否引起跃迁截面的类共振增强。首席研究人员已经展示了半经典的估计，给出了与实验相对应的增强截面。用一个简单的二能级模型进行了量子力学计算，但结果表明只给出了轻微的增强。为了理解这种差异，现在正在进行分析处理，例如，DWBA。为了进行上述研究，我们发展了一种新的形式，即体固定框架中的散射形式，它使我们能够适应双中心壳模型的散射问题。此外，我们还对分子共振的振动-转动模型进行了深入的研究。结果表明，忽略转动-振动耦合会导致完全误导的结果。

1. Investigations have been made on whether Landau-Zener level crossings in nuclear heavy-ion collisions cause resonance-like enhancements in transition cross sections. Semi-classical estimates were already shown by the head investigator to give enhanced cross sections corresponding to experiments. Quantum mechanical calculations have been performed with a simple two-level model, but have turned out to give only slight enhancements. In order to understand this difference, analytical treatments are now being pursuites, for example, by DWBA.2. In order to perform the above investigations, we have developped a new formalism, i.e., a scattering formalism in the body-fixed frame, which enables us to accomodate 2-center shell model in scattering problem.3. Furthermore, we have critically investigated the vibration-rotation models for molecular resonances. It has been shown that neglects of rotation-vibration couplings cause completely misleading results.