[Wien] Phase transition

[Víctor Luaña Cabal]

On Mon, Aug 31, 2015 at 04:39:15PM +0500, osama rana wrote:
> Hello,is there possible to check phase transition between two phases of
> same element or compound from E-V data obtain after optimization.?if not
> then kindly suggest some other method.
> Thank you in advance

To examine phase transitions you obtain the E(V) data and transform
that into the adequate thermodynamic potential. Under fixed pressure and
temperature conditions the potential to examine is the Gibbs function,
and the quasi harmonic approach can be used to introduce the thermal
effects. Some references may orient you:

MA Blanco et al, Comput. Phys. Commun. 158 (2004) 57
A. Otero-de-la-Roza and V. Luaña Comput. Phys. Commun. 182 (2011) 1708
   Phys Rev. B 84 (2011) 024109; 184103
A. Otero-de-la-Roza et al, Comput. Phys. Commun. 182 (2011) 2232

The MA Blanco article is particularly intensive.

wien2k also contains drivers to optimize the structure under fixed
pressure, but I suggest the indicated method as it provides (imho)
a more significative approach.

Best regards,
             Dr. Víctor Luaña
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