He-Na_2体系低温下的冷碰撞研究  

Low-temperature collisions of Na_2 with He

作　　者：王悦[1] 董德智[1] 李伟艳[1] 凤尔银[2] 崔执凤[2] 

机构地区：[1]铜陵学院电气工程系,铜陵244000 [2]安徽师范大学物理与电子信息学院,芜湖241000

出　　处：《物理学报》2009年第10期6913-6919,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10874001);教育部科学技术研究重点项目(批准号:208057);安徽省自然科学基金(批准号:070416236);铜陵学院自然科学基金(批准号:2008tlxykj005)资助的课题~~

摘　　要：在已经拟合好的He-Na2体系势能面上,根据原子-双原子分子的非反应性碰撞动力学的相关基本理论,在空间固定坐标系下,采用严格的密耦方法求解了He原子和Na2分子的转动非弹性碰撞动力学方程.并对He-Na2体系的微分散射截面、积分截面作了详细的分析,结果与实验符合得比较好.结果表明:(1)弹性散射(Δj=0)截面远大于非弹性截面;(2)较小Δj的跃迁主要产生前向散射,随着Δj的增加,后向散射的几率增加;(3)对非弹性碰撞,以Δj=2的跃迁为主;(4)微分截面上呈现由于量子干涉而形成的振荡结构,且随碰撞能的减小,振荡结构越加明显;(5)在较小碰撞能时,弹性截面上显现清晰的碰撞参数彩虹,这对减少冷却囚禁中分子损失是有利的.The close coupling calculation of rotationally inelastic collision of He with Na_ 2 is first performed by employing a recently computed ab initio potential energy surface.The process of rovibrational energy excitation and relaxation of Na_ 2 in collision with He has been studied in detail based on the single and double exitations coupled cluster with a noniterative perturbation treatment of triple excitations CCSD（T）potential energy surface.Our results are in good agreement with the experimental results.Our results show that ： （ 1 ） The elastic cross section（ Δj = 0） is much larger than the inelastic cross section. （2） The largest amplitude occurs at small scattering angles. At low Δj transition, the He projectile is predominantly forward scattering. Backward scattering occurs as Δj increases. （3） For inelastic cross section, the most effective transition is that with Δj = 2. （4） The fast narrow diffraction oscillations in the cross sections are the obvious characteristics for the low Δj inelastic transitions, which decreases with increasing j. （5）The elastic differential-cross-sections（DCS） provides a useful visualization of rotational rainbows at low translational energy. It is beneficial to reducing the loss in molecular cooling and trapping.

关 键 词：He-Na2体系 密耦方法 微分散射截面 积分截面 

分 类 号：O562.5[理学—原子与分子物理] U461.91[理学—物理]