[Pw_forum] Xcysden cann't give all atoms in theconventional cell.

[Axel Kohlmeyer]

On Tue, 10 Jun 2008, zhaohscas wrote:

hongsheng,

have you considered, that this "missing" atom could just 
be "too far away" (due to numerical inaccuracy) so that 
the code building the conventional cell, doesn't consider
it on the boundary anymore but in the next cell. please
see tone's explanation of how the algorithm works.

cheers,
   axel.

ps.: can you please fix your mailer to not send n+1 copies
for the same mail. thanks. a.

HZ> >If you have find a structure that xcrysden fails to generate proper
HZ> >convetional-cell build structure, I woule appriciate if you send me the
HZ> >associated file, so that I can investigate.
HZ> 
HZ> I give you the folllowing xsf file of Si, which is generated by me:
HZ> 
HZ> ------------------------
HZ> CRYSTAL
HZ> PRIMVEC
HZ> 3.819990 0.000000 0.000000
HZ> 1.909995 3.308208 0.000000
HZ> 1.909995 1.102736 3.119009
HZ> CONVVEC
HZ> 0 4.41094429 3.11900862                                                       
HZ> 3.81998981 -2.20547214 3.11900862                                         
HZ> 3.81998981 2.20547214 -3.11900862
HZ> PRIMCOORD
HZ> 9 1
HZ> 14 1.909995 1.102736 0.779752 0.000000 0.000000 0.000000
HZ> 14 0     0     0
HZ> 14     1.9100    1.1027    3.1190
HZ> 14     1.9100    3.3082         0
HZ> 14     3.8200    4.4109    3.1190
HZ> 14     3.8200         0         0
HZ> 14     5.7300    1.1027    3.1190
HZ> 14     5.7300    3.3082         0
HZ> 14     7.6400    4.4109    3.1190
HZ> --------------------------
HZ> 
HZ> Using the above xsf file, the xcrysden fails to generate one of the face-centered atom.
HZ> Please check it. 
HZ> 
HZ> Best regards,
HZ> Honsheng.
HZ> 
HZ> P.S.  I also give the above xsf and the snapshot of the conventional cell in the attachment, FYI.
HZ> 

-- 
=======================================================================
Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
   Center for Molecular Modeling   --   University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
=======================================================================
If you make something idiot-proof, the universe creates a better idiot.