VASP Forum

Hi,

I am trying to apply a broadening to my XAS spectra dependent on the energy relative to the fermi energy. Therefore, I would like to know the corresponding value of the fermi energy in reference to the energies in the printed dielectric function output. On the wiki, I found "The energies of the excitations are with respect to the energy levels of the core electron of interest," however, when I take the difference between the fermi energy and the core-state eigenenergy I noticed there is still ~7-10 eV offset between this value and the absorption onset of the XAS spectrum, so I am still missing a factor. How do I directly calculate the corresponding band energy values in reference to the outputted dielectric function energies?

Thanks!

Dear nsolan,

Could you please provide the input and output files for your calculations so that I can better understand the context?

In a semiconducting system, the core-state excitation occurs into the lowest unoccupied bands, so the offset you mentioned could simply be the energy difference between the Fermi level and the lowest conduction-band state.

Best,
Alexey