Electron impact elastic and ionization cross-sections for atomic nitrogen

Abstract

Electron impact elastic and differential elastic cross-sections have been calculated for atomic nitrogen for an incident electron energy of 2.0 Rydbergs. Also computed was the differential ionization cross-section for ejection of a 2p electron having a kinetic energy of 0.43 Rydbergs. Although no experimental results were found for direct comparison, reasonable agreement was obtained when the theoretical results were qualitatively compared with available data. The wave function of the atom-electron system was approximated by the superposition of t-wo states, these being the initial target state of the overall system and the final continuum state. The continuum state was treated by restricting the integration over momentum space to a narrow band of momentum for the ejected electron. This restriction caused the elastic and inelastic differential equation s to uncouple and allowed them to be solved separately instead of simultaneously as is usually the case in bound state calculations. Both the elastic and inelastic wave functions were determined numerically by means of a partial wave analysis. The effects of exchange were accounted for by expressing all wave functions in the form of a Slater determinant. It was found that for an incident energy of 2 Rydbergs, the inclusion of exchange is very important since the calculated differential elastic scattering cross-section was considerably different when exchange was neglected. Based on qualitative comparisons with available experimental results the method used in the investigation to calculate elastic and ionization cross-sections appears capable of being extended to other complex atoms.