[gpaw-users] Inplane force != zero

[Duy Le]

Some components go up to 0.05A/eV. I know the egg box effect, but I don't
think they can be that huge. I used h=0.20A. If  h is reduced to 0.18A,
those non zero forces could go up to 0.04A/eV.

I don't really understand your 2nd question. However, the structure was
generated by using ase.structure.bulk and grid-mesh was generated by
gpts(72,72,164). I don't see any problem in regarding the symmetry of
structure and grid mesh.

--------------------------------------------------
Duy Le
PhD Student
Department of Physics
University of Central Florida.

"Men don't need hand to do things"


On Tue, Jun 1, 2010 at 6:07 PM, Ask Hjorth Larsen <askhl at fysik.dtu.dk>wrote:

> Dear Duy Le
>
>
> On Tue, 1 Jun 2010, Duy Le wrote:
>
>  Dear All,I was relaxing 5 layer of Cu(111). For (1x1x5) slab, everything
>> is
>> great. However, for (5x5x5) slab, It is weird that the in-plane components
>> of forces (in Oxy plane) are not zero (they should be zero because
>> of symmetry).
>> I don't know what causes the problem (or maybe not).
>> Any comment will be great!
>>
>
> How nonzero are they?  Is the system symmetric also with respect to the
> structure of grid points?
>
> Regards
> Ask
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