Auger decay of quasiparticle states: Calculation of the Ni 3pphotoemission spectrum inNiCl2

We have calculated the Ni 3p x-ray photoemission spectrum (XPS) in ${\mathrm{NiCl}}_2$, taking into account the lifetime of Ni 3p hole states due to the ${\mathit{M}}_{2,3}$ ${\mathit{M}}_{4,5}$ ${\mathit{M}}_{4,5}$ super-Coster-Kronig decay process. We show that the LS-term dependence of the lifetimes strongly affects the whole spectral shape because the multiplet splitting of the 3p XPS is large. This indicates a breakdown of the assumption that the lifetimes of final states are the same, which has been widely adopted in the analysis of core-level excitation spectra.