Multiplet Splitting of Core-Electron Binding Energies in Transition-Metal Ions

X-ray photoelectron spectra indicate core-electron binding-energy splittings of ∼6 eV for the $3s$ levels in Mn${\mathrm{F}}_2$, MnO, and Fe${\mathrm{F}}_3$, and less pronounced effects on the $3s$ levels in Mn${\mathrm{O}}_2$ and Fe metal. These splittings are considerably reduced from free-ion predictions but agree well with calculations for Mn in a cluster environment. The $3p$ multiplet splittings are shown to behave in a quantitatively different fashion.