Electron impact single ionization for Si atom

Single ionization by electron impact is studied in the Si atom by performing level-to-level calculations. Direct and indirect processes of the ionization are investigated for all levels of the ground configuration. It is demonstrated that cross sections are heavily dependent on the initial level for which the ionization is considered. The cross sections of the indirect process differ by more than a factor of two for the lowest and highest levels of the ground configuration. The scaled distorted wave cross sections are used to explain experimental data. Modeling shows that similar to 70% of the atoms in the beam belong to the levels of the P-3 term. The cross sections and Maxwellian rate coefficients are tabulated for the electron-impact collisional ionization and excitation-autoionization processes. (C) 2020 Elsevier Inc. All rights reserved.