[Wien] optic sum rules

Elias Assmann elias.assmann at gmail.com
Tue Oct 1 11:42:04 CEST 2013

On 10/01/2013 11:24 AM, ali ghafari wrote:
> Actually, I have repeated the calculations again. I see the spectra are
> almost
> same for 2000 and 3000 kpoints but still there is a significant change
> in the spectra for 90000 kpoints.

As Xavier indicated in his PS, it almost certainly means that something 
is going wrong, though I cannot tell you what it is.

If you see no difference in epsilon between 2k and 3k k-points, I would 
say that means the mesh is converged for optics.  Even if you want to be 
very careful in your convergence test, keep in mind that all other 
optical quantities are calculated directly from epsilon.  The only other 
thing you could check is convergence in the energy range you calculate 
Im(eps) in, because the Kramers-Kronig needs it (in principle) from 0 to 

> how can I explain it? furthermore, when you said 2000, 3000 kpoints,
> your means is in the
>   BZ or IBZ?

In the full Brillouin zone.


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