X-ray emission and photoelectron spectra, and the location of fluorine atoms in strontium and calcium copper oxyfluorides

X-ray emission and photoelectron spectra of Sr2CuO2F2+δ, Sr1.4Ba0.6CuO2F2+δ, CaSrCuO2F2+δ, and Ca2CuO2F2+δ cuprates are presented. It is found that the XPS F 1s binding energies of Sr2CuO2F2+δ and Ca2CuO2F2+δ are different (ΔE ∼ 1.3 eV) and those of Sr1.4Ba0.6CuO2F2+δ and CaSrCuO2F2+δ have intermediate values. These differences in x-ray photoelectron spectra are attributed to the different preferential location of fluorine atoms in structures related to La2CuO4 and Nd2CuO4. The results obtained are in accordance with measurements of F Kα x-ray emission spectra of the same compounds.