Cross sections for K-shell ionisation by electron impact
Cross sections for K-shell ionisation by electron impact
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DOI：
10.1088/0953-4075/23/12/020
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发表时间：
1990-06
期刊：
影响因子：
--
通讯作者：
R. Mayol;F. Salvat
中科院分区：
文献类型：
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作者：
R. Mayol;F. Salvat
提出了一种计算相对论电子碰撞原子束缚壳层电离截面的半唯象方法。这种方法涉及一个简单的schematisation的贝特表面，这是从实验中获得的光学振子强度分布。作者的方法可以用来描述任何束缚壳层的电离。他们详细考虑的情况下，K-壳层电离，并推导出一个分析公式的微分截面的基础上的类氢光振子强度密度。近距离碰撞由穆勒微分截面描述，因此包含了交换效应。玻恩近似的电离阈值附近的能量的经验修正。讨论了它们的近似与Weizsacker-Williams虚量子方法的关系。
A semi-phenomenological method to compute the cross section for bound shell ionisation of atoms by impact of relativistic electrons is proposed. This method involves a simple schematisation of the Bethe surface, which is obtained from the experimental optical oscillator strength distribution. The authors' approach may be used to describe the ionisation from any bound shell. They consider in detail the case of K-shell ionisation and derive an analytical formula for the differential cross section on the basis of a hydrogenic optical oscillator strength density. Close collisions are described by the Moller differential cross section, thus incorporating exchange effects. Empirical corrections to the Born approximation for energies near the ionisation threshold are introduced. The relationship of their approximation and the Weizsacker-Williams method of virtual quanta is also discussed.