[Wien] Average electrostatic potential

[Rubel, Oleg]

It is my understanding that, in WIEN2k, the potential is represented differently in different regions of space. In the interstitial region it is expanded in Fourier components, and the G=0 Fourier component is set to zero by construction. However, the vanishing of the G=0 interstitial Fourier component does not automatically imply that the full cell-averaged potential is zero, because the potential inside the muffin-tin spheres is represented separately. Also, one should not assume that aligning to the "average potential” in the whole cell resolves the reference-energy ambiguity, because that quantity is itself not uniquely defined in a periodic solid. There were many discussions on this point in the past (search the list!).

If you still want to extract the electrostatic potential from a WIEN2k calculation, this functionality is available and documented. I would recommend checking the relevant sections of the WIEN2k user guide to see how the potential can be written on a real-space grid.

Maybe core electron energy levels could serve as a reference too? See Fig. 7 and 11 in doi: 10.1063/1.5110039

Hopefully this helps,
Oleg

> On Mar 18, 2026, at 10:35, uchit chaudhary <uchitchaudhary99 at gmail.com> wrote:
> 
>   Caution: External email. 
> Dear experts, 
> I am trying to reproduce the result, especially the VBM and CBM band edges and deformation potential, as mentioned in this article: https://doi.org/10.1038/srep22778. It has mentioned the average electrostatic potential is used as a reference for band edge energy (VBM and CBM) calculation. How to calculate average electrostatic potential and extract its value?
> 
> 
> Wien2k user
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> SEARCH the MAILING-LIST at:  http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html