[Pw_forum] Get wrong symmtry
Andrea Dal Corso
dalcorso at sissa.it
Mon Nov 10 07:31:07 CET 2008
Quoting 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?
This is not a problem of the code. Please check your z coordinates.
Note that they are in units of alat, not in units of c.
Andrea
>
> 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.
>>
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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
>
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