基于联合分离原子模型的电离理论  

A ionization theory based on united and separated atom model

作　　者：李明生[1] 蔡晓红[1] 

机构地区：[1]中国科学院近代物理研究所

出　　处：《物理学报》2007年第8期4448-4453,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10134010;10375080;10304019)资助的课题.~~

摘　　要：采用微扰静态(PSS)模型近似处理极化和结合能效应,并引入了相对论效应、能量损失效应和库仑偏转效应修正的ECPSSR理论是描述直接库仑电离过程最成功的理论,但对于低能离子入射时,其结果明显低于实验值.采用联合分离原子(USA)模型替代ECPSSR中的PSS模型,考虑分子轨道效应得到了基于USA模型的电离理论——MECUSAR理论.对部分碰撞系统进行了计算,得到的碰撞截面与实验结果基本符合.结合OBKN(Oppenheimer-Brinkman-Kramers formulas of Nikolaev)电子俘获模型,对MECUSAR理论进行了进一步修正,使其能对不同电荷态的入射离子进行计算.The direct Coulomb ionization process can be generally well described by the ECPSSR theory, which bases on the perturbed- stationary-state（PSS） and accounts for the energy-loss, Coulomb-deflection, and relativistic effects. But the ECPSSR calculation has significant deviations for heavy projectile at low impinging energies. In this paper we propose a new modified ECPSSR theory, i.e. MECUSAR, in which PSS is replaced by an united and separated atom model, and molecule-orbit effect is considered. The MECUSAR calculations give better agreement with the experimental data at lower impinging energies, and agree with the ECPSSR calculations at high energies. By using OBKN （Oppenheimer-Brinkman-Kramers formulas of Nikolaev） theory to describe the contribution of the electron capture, we further modified the proposed MECUSAR theory, and calculated the target ionization cross sections for different charge states of the projectile.

关 键 词：X射线产生截面 离子-原子碰撞 电子俘获 

分 类 号：O562.4[理学—原子与分子物理]