O^(3+)与氦原子碰撞过程的CTMC计算

CTMC calculation of O^(3+)+He impact processes

应用经典径迹蒙特卡罗方法研究了O3+离子与氦原子碰撞的各种反应过程.基于使用多个系统总能量U值,对初始电子的微正则分布进行了优化,使其更接近于量子力学的径向空间分布.作为检验,首先在独立电子模型近似下计算了He2+与氦原子碰撞的各种反应过程,通过与实验的比较,发现对氦原子靶,优化极大地提高了计算精度.计算了O3+与氦原子随入射离子能量变化的各种反应过程截面,特别是单电子丢失、双电子丢失的总截面,以及转移电离截面与单俘获截面的比值,并与实验进行了比较,发现单双电子丢失截面与实验符合得很好,但在大于200keV/u的能区,转移电离截面与单俘获截面的比值与实验有较大的差距,这表明独立电子模型需要进一步改进.

The O^3＋ ＋ He collision processes are studied ultilizing a classical trajactory Monte-Carlo （CTMC） method. The initial microcanonical distribution is modified by using eleven different ionization thresholds of electrons in tht target. The total cross sections of all pmcessess as functions of the projectile energy are calculated. For a test, the process of He^2＋ ＋ He is calculated and the agreement with experiment is improved by the modified distribution. The total cross sections of O^3＋ ＋ He including single- and double-electron ionization and transfer ionization are obtained in the energy range from 3 keV/u to 1 MeV/u, which are found in good agreement with the experiment. But there exists some large difference for the ratio of transfer ionization to single-electron capture, which requires further theoretical and experimental investigations.