[Pw_forum] k points in epsilon.x

[Andrea Ferretti]

Hi,

> Sir, i want to calculate dielectric constant as a function of frequency.  I
> have read the manual And it is written there that
> Epsilon.x doesn't support the reduction of the k-points grid into the
> unreducible Brillouin zone, so the previous PW runs must be performed with a
> uniform k-points grid and all k-points weights must be equal to each other,
> i.e. in the k-points card the k-points coordinates must be given manually in
> \emph{crystal} or \emph{alat} or \emph{bohr}, but not with the
> \emph{automatic} option.
> Thanks
>

I think this is correct..
a good procedure could be first to run a scf calculation using whatever
symmetrized kpt-mesh. Then you can run a nscf calculation with a suitable
number of empty bands (according to your needs) and a regular mesh of kpts
over the whole BZ.

andrea

DMSE, MIT
Massachusetts