Quantification of Ni L 2 , 3 core-hole relaxation pathways utilizing Auger photoelectron coincidence spectroscopy

Ni $LVV$ Auger spectra, in coincidence with the corresponding $2{p}_{1/2}$, $2{p}_{3/2}$, and $6\phantom{\rule{0.28em}{0ex}}\text{eV}$ satellite photoelectrons, have been used to examine electron correlation and itinerance effects in Ni. In coincidence with the $2{p}_{3/2}$ core level, the Auger spectral shape is represented by localized $3{d}^{8}$ and itinerant valence final states with an additional $3{d}^{7}$ Auger shake-up contribution. The spectra in coincidence with the $6\phantom{\rule{0.28em}{0ex}}\mathrm{eV}$ satellite probe the decay of localized $2{p}^{5}3{d}^{9}$ double hole states, leading to $3{d}^{7}$ final states. It is found that a fraction of the double hole states delocalize before the Auger decay. A similar delocalization is observed for the double hole states produced by the ${L}_{2}{L}_{3}{M}_{45}$ Coster-Kronig process, and the delocalization rates have been determined.