[Pw_forum] k-points for optical properties

[Eduardo Menendez]

Dear Paolo,
Thanks for your response. Yes, tetrahedra should work, but for large unit
cells  (108 atoms) I have problems because to obtain reasonable results the
k-mesh must be somewhat dense and I have a problem where the wfc occupy
more terabytes than allowed by the computer systems. I think I can combine
a coarse Monkhorst-Pack mesh with a dense mesh, but I have doubts on how to
set the weights at the interfaces between the coarse and the dense mesh. I
guess I should read on self-adaptative integration algorithms. Doing that,
I think I can run epsilon.x with with groups of few k-points and add the
dielectric functions obtained for each set.

>> Is there any available tool or method to generate non-uniform k-point
>> grids (and weights) useful to sample the van-Hove singularities in the
>> DOS or the joint DOS for calculations of dielectric function?

>not that I know. If however the goal is to obtain correct van Hove
>singularities, with tetrahedra you should obtain them.

Best regards,
Eduardo
Eduardo Menendez Proupin
Departamento de Fisica, Facultad de Ciencias, Universidad de Chile
URL: http://www.gnm.cl/emenendez

  “Science may be described as the art of systematic oversimplification.”
Karl Popper
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