FINAL-STATE SCREENING EFFECT IN THE 3S PHOTOEMISSION SPECTRA OF MN AND FE INSULATING COMPOUNDS

The satellite structures of 3s core-level photoemission spectra of Mn and Fe dihalides and monooxides have been studied systematically. We f ound that exchange splitting between 3s holes and 3d electrons, intras hell electron correlation, and final-state screening (charge-transfer satellite) effects all contribute to their satellite structures. We ex tended the existing model of 2p core-hole satellite structures for tra nsition-metal compounds [Park et al., Phys. Rev. B 37, 10 867 (1988)] to the case of 3s core holes by including the exchange interaction and the intrashell electron correlation effect. The intrashell electron c orrelation effect is included by introducing two parameters, the energ y separation and the coupling strength between 3s3d(n)underbar and 3p( 2)3d(n+1)underbar states. With this model, we were able to explain ver y well the 3s spectra of the Mn and Fe insulating compounds studied he re, and which were consistent with their 2p core-level spectra analyse s. We observe that the importance of final-state screening effects in the core-level spectra depends on the ligands. As a result, 3s energy splittings for very ionic compounds such as MnF2 and FeF2 can be well understood by exchange splitting alone, but that 3s splittings in othe r compounds in general are not directly related to the 3d local magnet ic moment of the ground state. We found that the change of 3s splittin gs in more covalent compounds is mostly determined by the final-state screening due to the different values of 3s-hole-3d-electron Coulomb a ttraction Q depending upon the spin of the final state, rather than th e exchange energy between 3s holes and 3d electrons.