The excitation of sodium-like argon ions by high energy projectiles

Abstract The Auger electron spectrum emitted by singly excited sodium-like argon ions has been investigated by means of high resolution 0° projectile Auger spectroscopy at high impact energy. The lines found m the experimental.spectrum were assigned to the corresponding Auger transitions by using the theoretical transition energies and their differences as well as the relative intensities (PWBA collision strengths) calculated using the configuration interaction Hartree-Fock code by Cowan. The Auger electron spectrum is due to the decay of levels m the sodium-like Ar populated by single monopole, dipole and quadrupole excitation by He atoms. The intensities due to monopole excitation are significantly higher than the PWBA expectation. The structure of the emitted electron spectrum is found to be greatly influenced by configuration interaction. The screening effect of the target electrons appears to be responsible for the deviation of the ratio of the intensities due to monopole and dipole excitation from the PWBA estimate.