The electronic structure of CoO is studied by resonant inelastic soft x-ray scattering spectroscopy using photon energies across the Co 2p absorption edges. The different energy-loss structures in the Raman scattering spectra are identified as due to d-d and charge-transfer excitations. For excitation energies close to the L3 resonance, the spectral features are dominated by quartet-quartet and quartet-doublet transitions of the 3d7 configuration. At excitation energies corresponding to the satellites in the Co 2p x-ray-absorption spectrum of CoO, the emission features are instead dominated by charge-transfer transitions to the 3d8L21 final state. The spectra are interpreted and discussed with the support of simulations within the single-impurity Anderson model with full multiplet effects which are found to yield consistent spectral functions to the experimental data.
Magnuson, M., Butorin, S. M., Guo, J. H., & Nordgren, J. (2002). Electronic structure investigation of CoO by means of soft x-ray scattering. Physical Review B - Condensed Matter and Materials Physics, 65(20), 1–5. https://doi.org/10.1103/PhysRevB.65.205106