[Pw_forum] Get wrong symmtry

[lan haiping]

hi, yumin,
you can install a  xcrysden to examine your input structures,
just with
" xcrysden --pwi  pw.inp"




On Mon, Nov 10, 2008 at 3:54 PM, yumin qian <yuminqian at gmail.com> wrote:

>
>     thanks for all of you ,
>    the problem have been solved by adding a parameter to the
> atomic_position card.
>
> ATOMIC_POSITIONS {crystal}
> 2008/11/10 yumin qian <yuminqian at gmail.com>
>
>     Thanks for your reply ,
>>  But what is the problem is ?
>>  I think there is nothing wrong to do with numerical accuracy , there may
>> be something wrong with the code itself , could anybody give me a suggestion
>>  to the solution of this problem?
>>
>> 2008/11/10 Michael Mehl <rcjhawk at gmail.com>
>>
>>  Axel Kohlmeyer wrote:
>>> > On Sun, 9 Nov 2008, yumin qian wrote:
>>>
>>> > how about not having enough numerical accuracy
>>> > for the numbers in the z-coordinate?
>>> >
>>> > axel.
>>>
>>> That would appear not to be the case.  The requirement for P4/nmm
>>> symmetry is that z for the second atom in a pair be equal to -z (or 1-z)
>>> for the first atom.  That's the case here.  Whatever the problem is,
>>> it's not in the coordinates.
>>>
>>> (See http://cst-www.nrl.navy.mil/lattice/struk/AsCuSiZr.html)
>>>
>>> >
>>>
>>> > YQ> ATOMIC_POSITIONS
>>> > YQ> La    0.2500000000    0.2500000000    0.1461000000
>>> > YQ> La    0.7500000000    0.7500000000    0.8539000000
>>> > YQ> O     0.7500000000    0.2500000000    0.0000000000
>>> > YQ> O     0.2500000000    0.7500000000    0.0000000000
>>> > YQ> Fe    0.7500000000    0.2500000000    0.5000000000
>>> > YQ> Fe    0.2500000000    0.7500000000    0.5000000000
>>> > YQ> As    0.2500000000    0.2500000000    0.6369000000
>>> > YQ> As    0.7500000000    0.7500000000    0.3631000000
>>>
>>> --
>>> Michael Mehl, Naval Research Laboratory, Washington DC.
>>> Sabbatical Duke University through July 2009.
>>>
>>> _______________________________________________
>>> Pw_forum mailing list
>>> Pw_forum at pwscf.org
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>>>
>>
>>
>>
>> --
>> Sincerely Y. M. Qian
>> Lab.of Condensed Matter Theory and Materials Computation
>> Institute of Physics
>> Chinese Academy of Sciences
>> Tel:  + 8610 8264 9147
>> E-Mail:yuminqian at gmail.com <E-Mail%3Ayuminqian at gmail.com>
>> P.O.Box 603   Beijing 100190
>> China
>>
>>
>
>
> --
> Sincerely Y. M. Qian
> Lab.of Condensed Matter Theory and Materials Computation
> Institute of Physics
> Chinese Academy of Sciences
> Tel:  + 8610 8264 9147
> E-Mail:yuminqian at gmail.com <E-Mail%3Ayuminqian at gmail.com>
> P.O.Box 603   Beijing 100190
> China
>
>
> _______________________________________________
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>


-- 
Hai-Ping Lan
Department of Electronics ,
Peking University , Bejing, 100871
lanhaiping at gmail.com, hplan at pku.edu.cn
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