Relativistic distorted wave approach to electron impact excitation of argon gas using a complex potential

Abstract In this study, we apply relativistic effects to excitation of the lowest lying resonance states of argon gas with inclusion of absorption, polarization and exchange effects to the electrostatic distortion potential to form an overall complex distortion potential. The atomic wave functions are constructed in the multi-configuration Dirac Fork approach by modifying the general-purpose relativistic atomic structure code GRASP for numerical procedures, while differential cross sections (DCS) and integral cross sections (ICS) have been obtained using our new code RDWBA1. Our results are compared with available experimental and theoretical results in literature. Present results from this study predict that use of a complex distortion potential in the relativistic approach to excitation of argon generally lowers integral and differential cross sections as impact energies of the incident electron increases, specifically beyond 50 eV, and that the energy dependent polarization potential adopted in this work plays a major role in improving shapes of cross-sections at near threshold impact energies up to around 30 eV, where available distorted-wave methods fail to give satisfactory results when compared to experiments.