中低能速度能区离子与H,He原子碰撞中的经典电子俘获截面  

Classical Electron Capture in Collisions of Ions with H,He Atoms at Low and Intermediate Velocities

作　　者：郭涛 惠新飞 丁宝卫[1] GUO Tao;HUI Xinfei;DING Baowei(School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,China)

机构地区：[1]兰州大学核科学与技术学院,兰州730000

出　　处：《原子核物理评论》2021年第2期210-214,共5页Nuclear Physics Review

基　　金：National Natural Science Foundation of China(11574123,10704030)。

摘　　要：Bohr-Lindhard模型被用来描述中低能速度能区离子—原子碰撞中的经典电子俘获过程。根据离子与原子的作用时间与碰撞参数的关系,建立俘获几率对碰撞参数的依赖性,碰撞参数范围被限定在俘获半径之内。在该模型的框架内,人们试图通过电子的空间分布函数来研究所有碰撞参数的贡献,但存在较为复杂的数值计算。基于Bohr-Lindhard模型,本工作提出通过简单的指数衰减函数来描述电子俘获几率对碰撞参数的依赖性,计算了A^(q+)(q=2~6)-H碰撞中的单电子俘获截面和A^(q+)(q=3~6)-He碰撞中的双电子俘获截面,计算结果与已有实验数据符合很好,很好地描述了低能和中能区的电子俘获截面随能量和电荷态的变化,该工作还可计算其他不同电荷态离子与He和H靶的电子俘获截面。The Bohr-Lindhard(B-L)model is used to describe the classical electron-capture process.The impact-parameter dependence of the capture probability is derived by considering the impact-parameter dependence of the collision time between ion and atom.This model limits the impact parameter to be less than the capture radius.In the framework of the B-L model,although the contribution from all impact parameters may be studied through the spatial distribution function of electrons,the multiple numerical integral has to be carried out.In this work,it is proposed that the impact-parameter dependence of the electron-capture probability can be given by a simple exponential decay function based on the(B-L)model.Electron-capture cross sections for A^(q+)(q=2~6)-H collisions,and double-electron-capture cross sections for A^(q+)(q=3~6)-He collisions are calculated at low and intermediate velocities.The calculated results are in good agreement with the existing experimental data.The energy and charge-state dependences of the electron-capture process are well described.This work can also be used to calculate the cross sections of electron capture from He and H targets by other ions with different charge states.

关 键 词：电子俘获 指数衰减函数 碰撞参数依赖 Bohr-Lindhard模型 

分 类 号：O562.5[理学—原子与分子物理]