[Wien] Space group clarification

[Peter Blaha]

It is very well described in the UG and was discussed and clarified 100 times in the mailing list.

R spacegroups require  "hexagonal lattice constants" and "rhombohedral atomic positions".

Am 11.01.2012 07:44, schrieb puday at iitk.ac.in:
> Dear
> Than you very much for your reply. But I am still in problem.
>
> I tried to convert R3-m:hexagonal (166)to R3-m: rhombohedral(166) using
> Bilbao Crystallographic Server.
> Here I put the initial lattice parameters for space group 166 R3-m:h and
> do Non-standard setting
> 166 R3-m:h
> [a] [b] [c] [alpha] [beta] [gamma]
> 4.4313 4.4313 23.71 90 90 120
> [type] [number] [WP] [x] [y] [z]
> A 1 - 0 0 0
> B 1 - 0 0 0.5
> C 1 - 0 0 0.2351
> After transforming I get an odd looking structure for the R3-m:r which is
> not correct
>
> 166 R-3m:r
> 8.3071 8.3071 8.3071 30.94 30.94 30.94
> 3
> A	1	-	0.000000	0.000000	0.000000
> B	1	-	0.500000	0.500000	0.500000
> C	1	-	0.235100	0.235100	0.235100
>
>
> Please help me out.
>
> Regards,
> Uday Bhanu Paramanik
> Dept.of Physics
> IIT Kanpur
> India
>
>
>> Someone can correct me if I'm wrong, but I think w2web only takes R-3m
>> in rhombohedral.  So if you have a R-3m in hexagonal, you have to
>> convert your hexagonal structure to rhombohedral.  Then, input the
>> rhombohedral values into w2web for the R lattice.
>>
>> Two methods you could use to convert:
>>
>> 1) use "hex2rhomb" script (in command line, not in w2web!) that comes
>> with Wien2k
>>       - See userguide page 40:
>> http://www.wien2k.at/reg_user/textbooks/usersguide.pdf
>>
>> or
>>
>> 2) use Bilbao Crystallographic Server
>>       - http://www.cryst.ehu.es/cryst/setstru.html
>>       - Instructions for converting:
>> http://zeus.theochem.tuwien.ac.at/pipermail/wien/2011-December/015823.html
>>
>> On 1/9/2012 12:55 PM, puday at iitk.ac.in wrote:
>>> Dear wien2k user
>>>
>>> I am using WIEN2k101. I'm interested in structural properties of a
>>> compound
>>> which has the hexagonal structure with space group 166 (R-3m).
>>> I make the case.struct using w2web web server. When I choose the space
>>> group as 166(R-3m), it automatically takes the rhombohedral axes. But it
>>> needed the hexagonal axes for the same space group.
>>>
>>> How can I choose the hexagonal exes for this?
>>>
>>>
>>> Regards,
>>> Uday Bhanu Paramanik
>>> Dept.of Physics
>>> IIT Kanpur
>>> India
>>> _______________________________________________
>>> Wien mailing list
>>> Wien at zeus.theochem.tuwien.ac.at
>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>>
>>
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>>
>
>
>
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-- 
-----------------------------------------
Peter Blaha
Inst. Materials Chemistry, TU Vienna
Getreidemarkt 9, A-1060 Vienna, Austria
Tel: +43-1-5880115671
Fax: +43-1-5880115698
email: pblaha at theochem.tuwien.ac.at
-----------------------------------------