Study of the Plasma Ion Screening Effect on the Level Delocalization, Radiation Properties and Electron Collision Ionization of Plasma-Immersed Hydrogen Atoms

This manuscript introduces a relativistic method to determine the electronic structure and electron collision ionization process of atoms placed in a semiclassical plasma. The method uses the effective interaction pseudo-potential derived for general two interacting charged particles taking into account the quantum mechanical and screening effects to model the plasma environment. The Dirac equation with the aforementioned pseudo-potential is solved numerically to obtain the bound state and continuous state wave functions. The method starts from the Dirac equation and thus includes the relativistic effects on the one-electron level. The effects coming from the Breit interaction and quantum electrodynamics corrections are included. As a representative example, we investigate the plasma electron screening effect and the plasma ion screening effect, separated and combined, on the level delocalization and electron collision ionization process of hydrogen atoms placed in a strongly coupled semiclassical plasma environment. Properties of the spectra such as energies, oscillator strengths, and relativistic energy shifts corresponding to bound states are determined. The relativistic distorted wave method is used to provide a consistent and elaborate description of the ionization cross sections of the electron collisions involved. Our results reveal that the plasma electron shielding effect contributes to a reduced ionization potential and oscillator strength, while increasing the electron impact ionization cross section, when compared with the results of an isolated scenario. When the plasma ion shielding effect is included, these observed alterations are further enhanced, highlighting the considerable role of the plasma ion shielding effect in this process. Our results are in agreement with other theoretical data. The present study not only extends the relativistic distorted wave approach to the analysis of collision processes in semiclassical plasmas and evaluates the impact of the plasma ion screening effect but also has practical implications for radiation physics, inertial confinement devices, and the interiors of stars.