[Wien] Phonon calculation

[Víctor Luaña Cabal]

On Thu, Apr 23, 2015 at 12:26:02PM +0300, Madesis Ioannis(John) wrote:
> This is why I specified that I work with phonopy. Phonopy, (if you don't  
> already know) requires all generated structures to be of P symmetry. To  
> be honest, this is not always possible since I cannot override Wien2K  
> algorith, which detects possible symmetries (initialization runs in  
> batch mode, inside a home-made script). For phonopy, all atoms must be  
> inequivalent, for proper results. Since I run FIRST all the  
> initializations, and keep a log file, I am in position to tell if the  
> spacegroup of all structures is P1, which again, is a primary target for  
> a good phonopy calculation.

John,

1) If you need to use P1 symmetry try a extremely small displacement
   of your atoms to force the reduction of symmetry you need.
2) Notice that symmetry is used by the codes to reduce the computational
   effort. The other route is better if you hace time, experience and
   the capacity to improve Phonopy: use symmetry in the analysis.

Regards,
       Dr. Víctor Luaña
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