Core Level Shifts / XPS -- experience with quaility of results?

[janh]

Dear VASP users,

I am doing some CLS estimates for an TM-oxide system and am trying to determine the best way to get "accurate qualitative" results. I increased the plane wave cutoffs, EDIFFG, and precision to accurate, but use the (converged) k-point mesh from the preceding structure optimization. I presently use the "accurate final state" approximation (ICORLEVEL=2).
I got a few results that are sensible in comparison to experimental data, although the shifts are sometimes overestimated by a factor of 2 (or ~1.5eV).

Does someone have experience with such calculations? Which kind of error bars do I have to expect, given that this is based on pseudopotentials, and which approximation is the best for comparison to XPS data?

Also I have this recent posting warning that core eigenstate energy calculations are not officially supported: http://cms.mpi.univie.ac.at/vasp-forum/ ... php?4.4927
What is the problem with that, and how can I test whether the calculation I am doing are not plagued by this problem?

Thanks,
Jan

(My old post: http://cms.mpi.univie.ac.at/vasp-forum/ ... php?4.3153)

[support_vasp]

Hi,

We're sorry that we didn’t answer your question. This does not live up to the quality of support that we aim to provide. The team has since expanded. If we can still help with your problem, please ask again in a new post, linking to this one, and we will answer as quickly as possible.

Best wishes,

VASP