冷原子-分子碰撞动力学的理论研究

Recent experimental success in producing ultra-cold molecules opened up new era of ultra-cold molecules. Ultra-cold molecules play important roles not only in testing fundamental principles of physics, but also is of siginificant practical importance in many areas, including quantum computation, high-resolution spectroscopy, control of chemical reactions etc.. Currently the methods used for cooling down molecules to the ultra-cold temperature using magnetoassociation and photoassociation technology have been successful only to a very limited number of alkali metallic molecular systems. Sympathetic colling technique offered a promising way to generate a much larger class of ultra-cold molecules. This cooling technique cools off molecules by letting them collide with ultra-cold atoms. Thus, understanding of cold collision dynamics between atoms and molecules is of great importance. The major purpose of this project is to develop an efficient theoretical and computational methodologies suitable for the studies of cold atom-molecule collision dynamics, based on the works on quantum scattering dynamics the applicant has accumulated over many years. These methodologies will then be applied to various real molecular systems to carry out accurate quantum dynamics calculations, providing useful theoretical data to experimentalists to produce more number of ultra-cold molecules efficiently.

最近实验上超冷分子的成功制备宣告超冷分子时代的来临。超冷分子不仅在检验物理学基本原理方面发挥重要的作用，而且在量子计算，高分辨光谱学，化学反应的控制等领域有着无穷的应用前景。目前利用磁复合（magnetoassociation）或光复合（photoassociation）技术把分子冷却到超冷温度局限于几个少数碱金属分子体系。为了制备更多的超冷分子，sympathetic冷却提供了一个可靠的途径。也就是分子通过与超冷原子的碰撞进行冷却。所以原子与分子之间冷碰撞动力学的研究具有重大意义。本项目的主要目的是在申请人过去多年来积累的量子散射方面的工作基础上，发展一套有效的，适合处理冷分子碰撞动力学的理论，计算方法。并利用此方法对超冷条件下的实际分子体系进行精确的量子动力学计算，为实验上成功制备更多的超冷分子提供有用的理论数据。

通过本项目的资助我们发展了一套可用于处理超冷条件下原子-分子间碰撞动力学的理论计算工具。我们还提出了两种高效的势能面拟合算法并利用此算法对NH2和LiHCl分子体系构建了高精度的从头算势能面。我们利用开发的计算程序库对多个分子体系的碰撞动力学展开了精确的量子动力学研究。