Hi,
The open_grid.x code with automatic grid of k points in the scf input file
produces k points between -0.5 and 0.5 (crystal coords). However, the EPW code
requires wave functions for full set of k points from 0 to 1 in the first BZ
and gives an error when using k points between -0.5 and 0.5:
Error in routine epw_setup (1):
coarse k-mesh needs to be strictly positive in 1st BZ
Unfortunately this is a hybrid functional calculation, so I cannot perform nscf
calculation or use all k points in scf due to high memory requirement.
Therefore, I tried using the kpoints.x code in the PW/tools to generate IBZ k
points between 0 and 1 and specified the weights in scf file. On running
open_grid.x on this calculation, I get the error:
Error in routine exx_grid_init (1):
wrong EXX q grid
Is it not possible to use open_grid.x other than for automatically generated
k-points (runs fine in that case)? And is there a way to generate the files for
full set of k-points between 0 and 1 instead of -0.5 and 0.5?
The files for reproducing the error are at:
https://gitlab.com/ahzeeshan/qe-issues/-/tree/master/open_grid
<https://gitlab.com/ahzeeshan/qe-issues/-/tree/master/open_grid>
I used a 4 by 4 by 2 grid of k-points to generate the IBZ using kpoints.x code.
Thanks for your help,
Zeeshan
--
Zeeshan Ahmad
Postdoctoral Scholar
Pritzker School of Molecular Engineering
The University of Chicago
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