High-resolution ArL-shell Auger spectroscopy in 80-MeVAr5++He collisions

Auger-electron spectra produced in the collision of 80-MeV ${\mathrm{Ar}}^{5+}$+He were measured with high resolution. The spectra are dominated by the Auger decay of the ${\mathrm{Ar}}^{6+}$ projectile in a configuration with a hole in the 2p shell. All of the observed transitions can be identified by means of multiconfiguration calculations for transition energies. The line intensities are compared with transition rate calculations using the intermediate-coupling scheme. The observation of an Auger transition, which is forbidden in the single-configuration picture, is interpreted as being due to electron-correlation effects.