Core-level calculation in charged supercell
I have a supercell (metal oxide; 3D bulk) that has been fully optimized with an oxygen vacancy in a 2+ charge state. More precisely, I created an O vacancy, removed 2 electrons from the supercell and relaxed the entire structure. I now want to see how this vacancy modifies the core-level spectra of the neighboring metal atoms.
My question is whether running a core-level calculation in the final-state approximation (ICORELEVEL = 2) is compatible with charged supercells. The VASP documentation mentions that the core electron is moved to the valence, effectively increasing NELECT by 1 (or CLZ), which would require a neutralizing background. Given that the supercell already requires a neutralizing background from the outset, does the core-level calculation take this into account properly, i.e., use a net neutralizing background that effectively compensates 1 missing electron (2 electrons originally removed plus the 1 electron added from core level)?
I don't expect that the initial-state approximation should pose any such issues but please let me know if that is also potentially problematic for charged supercells.