Study of electron impact differential cross-sections of Kr (4p) and Ar (3p) in the perpendicular plane

Abstract The triple differential cross-section (TDCS) results are reported for the electron impact ionization of Kr (4p) and Ar (3p) atoms in the perpendicular plane geometry at projectile energies 40–120 eV and 40–200 eV above the ionization potential, respectively. In this geometry, scattered and ejected electrons are emitted perpendicular to the incident beam, providing a stringent test of theoretical models. Using the distorted wave Born approximation with correlation-polarization potential and post-collision interaction (PCI), we find the target polarization to be significant at these intermediate energies, while PCI effects are minimal. The TDCS exhibits a two-peak structure for both Kr and Ar, distinct from earlier He and Ne ionization studies, suggesting that kinematics dominate over the target structure. Our results show reasonable agreement with the experimental data, although some discrepancies indicate the need for further theoretical refinement. This study provides the first theoretical analysis of recent measurements, for which no prior theoretical estimates are available, highlighting many-electron effects in Kr and Ar ionization and advancing our understanding of ionization mechanisms.