[Pw_forum] Sym.Ops

[Gabriele Sclauzero]

On 07/21/2010 10:59 AM, Masoud Nahali wrote:
> Dear PWscf Users
>
> For the graphite bulk, in the output file I see "24 Sym.Ops." but for 
> the graphite surface (a slab with 10 angstrom vacuum) I see "6 
> Sym.Ops." . Is this plausible and correct ?

The symmetry operations are determined correctly in the code. The 
symmetry group that you get for a graphite slab depends on which type of 
graphite you consider  (i.e. hexagonal or Bernal) and how you build your 
slab. If your system has a mirror plane coinciding with z=0 (assuming z 
to be the stacking direction), then you will get 24 operations for an 
hexagonal graphite slab and 12 for a Bernal graphite slab (which is the 
maximum of the symmetry operations possible for each of the two systems).
To get more information about the symmetry on the output you can specify 
verbosity='high'.


HTH

GS


> I appreciate your help.
>
> Many Thanks
> Masoud Nahali
> SUT
>
>
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-- 

Gabriele Sclauzero, EPFL SB ITP CSEA
PH H2 462, Station 3, CH-1015 Lausanne

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