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The results of measurements of O $1s$ total x-ray-fluorescence yield and Ru ${N}_{2,3}$ and O ${K}_{\ensuremath{\alpha}}$ x-ray fluorescence emission spectra of ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ and ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4.25}$ are presented. An excitation energy dependence of the O ${K}_{\ensuremath{\alpha}}$ x-ray emission spectra (XES) was observed in both compounds. The energy dependence of the spectra is attributed to the excitation of inequivalent O (1) in-plane and O(2) apical oxygens. The O(1) $2p$ and O(2) $2p$ density of states distribution in the valence band of ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ was found to be different in accordance with the results of band-structure calculations. O(1) $2p$ states are found to be mixed with Ru ${4d(t}_{2g})$ states providing the formation of $\ensuremath{\pi}$ bonds. While the O ${K}_{a}$ XES spectra are in fair agreement with band structure calculations, the theoretical two-peak distribution of Ru ${N}_{2,3}$ XES is found to be different with respect to the intensity ratios and widths of the peaks of Ru ${N}_{2,3}$ XES. These differences are attributed to a decrease of intensity of radiative $4\stackrel{\ensuremath{\rightarrow}}{d}4p$ transitions in the vicinity of the Fermi level (where the localization of Ru $4d$ states is higher than at the bottom of the valence band) due to a strong Koster-Kronig transition.

X-ray absorption, resonant x-ray emission, and x-ray photoelectron spectra of the valence band and core levels have been measured for LixCoO2 (0.6

We present Mn $3s$ x-ray photoelectron spectra of manganese oxides with the Mn formal valency from $2+$ to $4+.$ We found that the ${\mathrm{Sr}}^{2+}$ doping or cation deficiency in manganites do not change the Mn $3s$ splitting in manganites with the Mn formal valency from $3.0+$ to $3.3+.$ We suggest that doping holes are localized in O $2p$ states.