[QE-users] Symmetry - Centered cell reduction

[Fnukal Frantisek]

Dear QE users,


I've studied the possible ways of inputing structural data and I found there basically were 3 ways. 1) Using ibrav = 0, so in essence saying: "Find it yourself" 2) Specifying the space group 3) Specifying the Bravais lattice with ibrav.

So far I've been using ibrav = 0, however output files keep telling me this way is not recommended as it may not correctly recognize symmetry in some cases.

However, I have a very important problem with the other 2 ways of inputing data. I've noticed they both automatically perform transformation to primitive cell if I input a structure in centered cell. My problem is with k-points. If I want to have an equivalent amount of k-points in the primitive cell, then I have a smaller system, but more k-points and in some cases this may lead to completely erasing any profit gained by reducing the system. I would very much like to control whether the transformation is applied or not.

My question is this: Is there any way of inputing structural data, preferably with space group, and turn off automatic centered cell to primitive cell conversion?


Thank you for your answers.


Best regards,

Frantisek Fnukal

UCT Prague