Electron-impact excitation of the lowest four excited states of argon

Abstract

First-order many-body theory has been used to calculate the differential and integral cross sections for electron-impact excitation of the argon atom to the $4^{3}P_{0}$, $4^{3}P_{2}$, $4^{3}P_{1}$, and $4^{1}P_{1}$ electronic states, for incident electron energies of 16, 20, 30, 50, and 80.4 eV. The resulting cross sections are in good agreement with recent results extracted from electron energy-loss measurements on argon. Detailed calculations show that spin-orbit coupling must be included in the $^{3}P_{1}$ wave function in order to describe the electron-impact excitation of the state properly.