Distorted-wave calculation of cross sections for inner-shell ionization by electron and positron impact
Distorted-wave calculation of cross sections for inner-shell ionization by electron and positron impact
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DOI：
10.1103/physreva.67.062710
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发表时间：
2003-06
影响因子：
2.9
通讯作者：
S. Segui;M. Dingfelder;F. Salvat
中科院分区：
文献类型：
--
作者：
S. Segui;M. Dingfelder;F. Salvat
相对论扭曲波玻恩近似用于计算电子和正电子撞击中性原子内壳电离的微分截面和总截面。使用自洽狄拉克-福克-斯莱特势在独立电子近似中描述目标原子。射弹的扭曲势也设置为等于狄拉克-福克-斯莱特势。对于电子来说，这保证了所有涉及的轨道的正交性并简化了交换 T 矩阵元素的计算。假设射弹和目标电子之间的相互作用减少到瞬时库仑相互作用。采用的数值算法可以计算动能范围从电离阈值到该值约十倍的弹丸的微分横截面和总横截面。通过将我们的代码计算的微分横截面（将扭曲势设置为零）与使用传统平面波玻恩近似的更稳健的代码生成的等效结果进行比较，证明了算法的准确性和稳定性。给出了各种元素的 K 和 L 壳层电离的示例计算结果，并与可用的实验数据进行了比较。
The relativistic distorted-wave Born approximation is used to calculate differential and total cross sections for inner shell ionization of neutral atoms by electron and positron impact. The target atom is described within the independent-electron approximation using the self-consistent Dirac-Fock-Slater potential. The distorting potential for the projectile is also set equal to the Dirac-Fock-Slater potential. For electrons, this guarantees orthogonality of all the orbitals involved and simplifies the calculation of exchange T-matrix elements. The interaction between the projectile and the target electrons is assumed to reduce to the instantaneous Coulomb interaction. The adopted numerical algorithm allows the calculation of differential and total cross sections for projectiles with kinetic energies ranging from the ionization threshold up to about ten times this value. Algorithm accuracy and stability are demonstrated by comparing differential cross sections calculated by our code with the distorting potential set to zero with equivalent results generated by a more robust code that uses the conventional plane-wave Born approximation. Sample calculation results are presented for ionization of K- and L-shells of various elements and compared with the available experimental data.