X-ray spectroscopy and electronic structure of MoO2

• An electronic structure analysis of MoO2 based on an extended cluster model was performed.
• Both local and nonlocal screenings are necessary to describe MoO2 electronic structure.
• A highly mixed covalent Mott-Hubbard regime is confirmed by the calculations.
• Mo L3 resonant photoemission spectra of MoO2 is presented for the first time.

We study the electronic structure of MoO2 using an extended cluster model. The calculations confirm that the compound is in a highly mixed covalent Mott-Hubbard regime. These results are then compared to other calculations and to x-ray absorption and (resonant) photoemission spectroscopies. The good agreement with the experimental spectra indicates a strong covalent character for the Mo 4d-O 2p bond. Finally, we show that, not only local charge fluctuations from the oxygen ions are necessary, but also nonlocal screenings, from the Mo dimer and from coherent (metallic) states, must be included in the description of the electronic structure of MoO2.