Relative effect of extra-atomic relaxation on Auger and binding-energy shifts in transition metals and salts

Abstract

The relation between shifts in Auger energies and shifts in electron binding energies is explored. The prediction of Auger energies in metals from one-hole and two-hole optical energies as well as from electron binding energies in metals is described, with proper accounting for final-state coupling, relaxation, and reference energies. A decrease in values of extra-atomic relaxation energies for $3d$ metals between Ni and Cu, arising from the loss of $d$-wave screening at the $3d$-shell closure, was derived for the $L_3{M}_{23}{M}_{23}$ Auger transition in which the final state is localized. A similar decrease can be derived from the data on the $L_3{M}_{45}{M}_{45}$ transition, suggesting that the $3d$ hole state may be localized. Shifts in either Auger or electron binding energies between solids have no direct significance when taken alone, but the difference between the two is shown to be equal to the difference in the corresponding extra-atomic relaxation energies. Differential shifts are reported for sodium and its salts and for zinc and its salts. The differential shift between sodium metal and NaF is 8.7 eV, while the Zn-to-Zn${\mathrm{F}}_2$ shift is 5.2 eV, in good agreement with expectations. The $\mathrm{Zn}\mathrm{}\left(3d\right)\mathrm{}-\mathrm{F}\mathrm{}\left(2p\right)\mathrm{}$ peak in the Zn${\mathrm{F}}_2$ spectrum gives clear evidence for crystal-field splitting in the final state.