[Pw_forum] (no subject)

[Axel Kohlmeyer]

And I told you that the code uses the primitive cell. 

--
Dr. Axel Kohlmeyer  akohlmey at gmail.com  http://goo.gl/1wk0
International Centre for Theoretical Physics, Trieste. Italy.

-----Original Message-----
From: Reza Behjatmanesh-Ardakani <reza_b_m_a at yahoo.com>
Date: Wed, 11 Dec 2013 11:44:07 
To: akohlmey at gmail.com<akohlmey at gmail.com>; PWSCF Forum<pw_forum at pwscf.org>
Reply-To: Reza Behjatmanesh-Ardakani <reza_b_m_a at yahoo.com>
Cc: Paolo Giannozzi<paolo.giannozzi at uniud.it>
Subject: Re: [Pw_forum] (no subject)

Unfortunately, our languages are not the same. I talk about conventional cell, but you talk about primitive cell. My problem is about P.B.C. in the code.  

With the Best Regards


Reza Behjatmanesh-Ardakani
Associate Professor of Physical Chemistry
Address:
Department of Chemistry,
School of Science,
Payame Noor University (PNU),
Ardakan,
Yazd,
Iran.
E-mails: 
1- reza_b_m_a at yahoo.com (preferred),
2- behjatmanesh at pnu.ac.ir, 
3- reza.b.m.a at gmail.com.



On Wednesday, December 11, 2013 10:46 PM, Axel Kohlmeyer <akohlmey at gmail.com> wrote:
  
Again. There is only one independent particle and there are no symmetry operations involved and no positions generated. Please look it up and don't speculated and guess. 
--
Dr. Axel Kohlmeyer  akohlmey at gmail.com  http://goo.gl/1wk0
International Centre for Theoretical Physics, Trieste. Italy.

________________________________

From:  Reza Behjatmanesh-Ardakani <reza_b_m_a at yahoo.com> 
Date: Wed, 11 Dec 2013 11:05:56 -0800 (PST)
To: Axel Kohlmeyer<akohlmey at gmail.com>; PWSCF Forum<pw_forum at pwscf.org>
ReplyTo:  Reza Behjatmanesh-Ardakani <reza_b_m_a at yahoo.com> 
Cc: Paolo Giannozzi<paolo.giannozzi at uniud.it>
Subject: Re: [Pw_forum] (no subject)

Yes, of course it has 4 independent particles. But my main problem is about the algorithm of periodic boundary condition in the code. You must introduce the shared atoms in the unit cell or not. I think the symmetry operators produce these positions automatically.

With the Best Regards


Reza Behjatmanesh-Ardakani
Associate Professor of Physical Chemistry
Address:
Department
 of Chemistry,
School of Science,
Payame Noor University (PNU),
Ardakan,
Yazd,
Iran.
E-mails: 
1- reza_b_m_a at yahoo.com (preferred),
2- behjatmanesh at pnu.ac.ir, 
3- reza.b.m.a at gmail.com.



On Wednesday, December 11, 2013 10:28 PM, Axel Kohlmeyer <akohlmey at gmail.com> wrote:
  
On Wed, Dec 11, 2013 at 7:47 PM, Reza Behjatmanesh-Ardakani
<reza_b_m_a at yahoo.com> wrote:
> Suppose, we have a simple fcc unit cell. Do we need to introduce one
> particle position (original particle) or 14 particles (8 on corners and 6 on
> the faces). I think only
 originals needed. Other particles can be produced
> by symmetry operators.

nope.

a fcc lattice has only one atom. that is in the *primitive* cell
(which is what QE uses). what you describe is the conventional cell,
which would be a simple cubic lattice but that would not have 14 atoms
but 4 atoms (1 in the corner and 3 in the faces, because the corners
are shared by 8 cells and the faces by 2).

i suggest you re-read the chapters covering these topics in your
favorite book on crystallography to work this out.

axel.

>
> With the Best Regards
>
>
> Reza
 Behjatmanesh-Ardakani
> Associate Professor of Physical Chemistry
> Address:
>
 Department of Chemistry,
> School of Science,
> Payame Noor University (PNU),
> Ardakan,
> Yazd,
> Iran.
> E-mails:
> 1- reza_b_m_a at yahoo.com (preferred),
> 2- behjatmanesh at pnu.ac.ir,
> 3- reza.b.m.a at gmail.com.
>
>
> On Wednesday, December 11, 2013 7:19 PM, Paolo Giannozzi
> <paolo.giannozzi at uniud.it> wrote:
> On Wed, 2013-12-11 at 07:12 -0800, Reza Behjatmanesh-Ardakani wrote:
>
>> 1- For preparing the input file, if you introduce a symmetry in your
>> input's structure, only original particles
>>    should be defined in the input file. Is it right?
>
> no: you need to supply all atoms in a unit cell.
>
>
> P.
>
> --
> Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
>
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum



-- 
Dr. Axel Kohlmeyer  akohlmey at gmail.com  http://goo.gl/1wk0
International Centre for Theoretical Physics, Trieste. Italy.
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