[Pw_forum] lattice constant from unit cell vs. from supercell

[Duy Le]

Not really sure if I understand your question. However, there seems to
be an incorrectness.
Simple logic:
1F, 2 C in a "1x1" supercell
4F, 8 C in a "2x2" supercell
--------------------------------------------------
Duy Le
PhD Student
Department of Physics
University of Central Florida.

"Men don't need hand to do things"



On Wed, Mar 17, 2010 at 12:52 PM, Paolo Giannozzi
<giannozz at democritos.it> wrote:
> Chad Junkermeier wrote:
>
>> If I do this using the unit cell, everything seems to
>> work correctly, and the equilibrium lattice constant for the system
>> seems to be correct.  If, instead, I use a 2x2 supercell I find that
>> the equilibrium lattice constant is not the same (or even close) to the
>> unit cell result.
>
> your data are for fixed-cell structural optimization: what do you mean
> by "the equilibrium lattice constant is not the same"? You choose the
> lattice constant
>
> P.
> --
> Paolo Giannozzi, Democritos and University of Udine, Italy
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