I think the forces are zero because of symmetry in the bulk. You should try
vc-relax.
On Wed, Apr 2, 2014 at 3:08 PM, Mutlu COLAKOGULLARI wrote:
> Hello People,
>
> I want to relax CoPt bulk material. It has face-centered tetragonal (tP4)
> structural type. The relaxation is always finisihing
Hello People,
I want to relax CoPt bulk material. It has face-centered tetragonal
(tP4) structural type. The relaxation is always finisihing after 1 scf
cycle and 0 bfgs step. The forces are always zero. I mean the system is
not relaxing. I googled the problem and I tried something in input,
Hi,
very likely this is related with the symmetry of your starting configuration.
By default, QE uses symmetry. All forces which must be zero by symmetry, are
NOT computed but SET to zero.
This is helpful because saves computing time, but can induce errors if the
starting configuration as a
Dear Mutlu,
There are no degrees of freedom to relax, the system has such high a
symmetry (P4/mm'm'?) that by that symmetry all the forces are zero. You
have to break the symmetry by shifting the atoms if you want non-zero
forces. If you want to relax the lattice vectors, please use
Have you already tried to use vc-relax instead of relax?
vc-relax = variable cell relaxation.
relax = internal coordinates relaxation.
I would say you have nothing to optimize in terms of internal coordinates:
you are using a high simmetry crystal that is written in terms of the
lattice
Hello People,
I want to relax CoPt bulk material. It has face-centered tetragonal (tP4)
structural type. The relaxation is always finisihing after 1 scf cycle and 0
bfgs step. The forces are always zero. I mean the system is not relaxing. I
googled the problem and I tried something in input,
Hello People,
I want to relax CoPt bulk material. It has face-centered tetragonal (tP4)
structural type. The relaxation is always finisihing after 1 scf cycle and 0
bfgs step. The forces are always zero. I mean the system is not relaxing. I
googled the problem and I tried something in input,
