[QE-users] Symmetry Operations in Reciprocal Space

[Lorenzo Paulatto]

> A follow up question:
> I used two different systems with the same point group symmetry. I used 
> the same density of the Monkhorst Pack grid of 8x8x6. But the resultant 
> number of reduced k vectors when using nosym=.false. and noinv=.false. 
> are different?
> As mentioned in the previous post, I am trying to manually reduce the k 
> point grid into the irreducible set of k points using the symmetry 
> Operations that is printed in the output of the scf calculation?
> Can some suggest me what is it that I am doing wrong?
> 


Dear Ankit,
when the grid of k-point is less symmetric than the crystal, strange 
things can happen. This has been discussed many times, I recommend 
reading the associated issue in the tracker:
https://gitlab.com/QEF/q-e/issues/2

There is no simple solution for the moment as it is often a combination 
of unnecessarily complicated code and unreasonable expectations of the user.

hope this applies to your question.

regards



-- 
Lorenzo Paulatto - Paris