Similarities in the screening effects of the core level and valence band spectra of V O2

We calculated the core level and valence band spectra of V O2 using an extended cluster model. The distribution of spectral weight is similar in both core level and valence band spectra and is related to the different screening mechanisms. Namely, the low energy structures in the spectra correspond to well screened final states, whereas the poorly screened final states appear at higher energies. The latter produce the charge transfer satellite observed in the core level spectra, and are related to the resonance in the constant initial state spectra of the valence band. The changes in the spectral weight across the metal-insulator transition are due to the different non-local screening channels present in each phase, and are also similar in both core level and valence band spectra. The calculation also shows a relatively large O 2p contribution in both spectra, which, in turn, helps to explain the enhancement of the coherent feature at higher photon energies. This suggests that the incoherent peak cannot be solely attributed to the lower Hubbard band.