类氦离子的电子碰撞电离微分截面

本文主要利用扭曲波玻恩交换近似方法(DBE)计算类氦离子在电子碰撞下,相应不同的末态电子能量分配的电离截面(能量微分截面)。发现对这些微分截面在不同靶电荷及入射能量下,都可用带两个参数的高斯函数αexp(β(x—0.5)²)很好地拟合。还给出两个拟合参数随靶电荷和入射能量的变化曲线,以及讨论了在库仑波玻恩交换近似(CBE)和DBE两种不同近似下所得参数值的差别。计算结果也表阴,在低靶电荷和低入射能量时用DBE计算的必要性。关键词：

DIFFERENTIAL CROSS SECTIONS FOR ELECTRON IMPACT IONIZATION OF HELIUMLIKE IONS

The electron impact ionization cross sections for different energy assignment on two final-state electrons (energy differential cross sections) of heliumlike ions have been calculated by using a disrored-wave Born exchange approximation. We found that the dependence of the differential cross sections on the scaled energy of secondary electrons can be well fitted with a two-parameter Gaussian function. The dependence cf two parameters on the incident electron energy and target charges have been given. The differences between the results from CBE (Coulomb-Born exchange approximation) and DBE calculations have been discussed. They show that it is necessary to use DBE calculation for low target charges and low incident en-