[CPMD-list] how to construct a crystallin system?

[Axel Kohlmeyer]

On Tue, 29 Apr 2008, mano mano wrote:

DM> 
DM> Dear cpmd users,

dear djamila,

DM> Excuse-me dear colleagues, today, I have a purely technical problem.
DM> 
DM> Until now, I used cpmd for isolated molecules ( from Axelÿÿs tutorial exemples),
DM> And I want to perform now, optimization for a crystalline system ( monoclinic
DM> crystallin system, with Z=2 (two molecules per cell)) .
DM> 
DM> I have two questions  concerning that :
DM> 
DM> 1) With which code could I construct the primitive cell of this crystallin compouds
DM> or others ? (I know that molden do conversion from other format to cpmd input, but
DM> it doesnÿÿt  construct crystallin compounds).

please have a look at, e.g,:
http://www.vlab.msi.umn.edu/events/download/tutorial_wyckoff.pdf

this is for a different code, but the principles 
apply to CPMD as well.

DM> 2) Must the Positions of the different atoms in the cell be put according to X-ray
DM> data , or I have just to insert the molecules according to the density, and how
DM> does this influence my results ?

please explain the difference. i don't see it.

cheers,
   axel.


DM> 
DM> Thank you much in advance,
DM> 
DM> Cheers,
DM> 
DM>  Djamila
DM> 
DM> 
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-- 
=======================================================================
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
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