L23[L23]−MM[L23]andL23[M2]−MM[M2]Auger vacancy satellite spectra of argon

Abstract

The deexcitation of a $1s$ core hole in argon via parallel Auger cascade branches leads to the emission of several superimposed ${L}_{23}\ensuremath{-}MM$ vacancy satellite spectra. These spectra arise from the presence of various configurations of additional ``spectator'' holes left by preceding Auger transitions. Such spectator vacancies (henceforth enclosed by brackets) cause characteristic energy shifts and a more complicated multiplet splitting. The most intense lines of the superimposed spectra have been successfully assigned previously. Here we present an extensive refinement and augmentation of that work. The experimental analysis obtained for the two particular ${L}_{23}\ensuremath{-}MM$ satellite spectra arising from the principal ${K\ensuremath{-}L}_{23}{L}_{23}$ deexcitation branch is compared to multiconfiguration Dirac-Fock calculations of energies and intensities. Excellent agreement is found, enabling an almost complete assignment of the recognizable lines. Furthermore, by comparison with the electron impact excited ${L}_{23}\ensuremath{-}MM$ spectrum a number of other lines are attributed to the normal ${L}_{23}\ensuremath{-}MM$ and the ${L}_{23}[M]\ensuremath{-}MM[M]$ satellite spectrum, which here originate, respectively, from concomitant single primary ${L}_{23}$ and ${L}_{1}$ ionization. We believe this to be the first comprehensive analysis of a compound Auger cascade spectrum.