The ABINIT Users Mailing List ( CLOSED )

[Razvan Caracas <r.caracas@gl.ciw.edu>]

oliver.potzel@chemie.uni-ulm.de wrote:

> Hello
>
> I'm interested in defining a cell only by using the spacegroup and the 
> Wyckoff positions. Did anyone ever try this?
>
> Oli
>  
Dear Oli,

You can define your cell in a variety of ways. One way to do it is just 
list the atomic coordinates (from the wyckoff positions if you want) in 
the assymmetric cell and specify the space group. Something like:

natom 12          !total number of the atoms in the whole unit cell: 
must be defined
natrd 3             !number of atoms to be read = number of atoms in the 
assymetric cell
xred                  ! fractional positions of the natrd atoms in the 
assymetric cell
0.1 0.1 0.1        
0.2 0.2 0.2
0.3 0.3 0.3
spgroup 128      ! space group number

For the non-standard orientation or origin of the space groups you have 
to use the spgaxor, spgorig. You find their meaning at:
~/Infos/spacegroupfile.htm

You can also define the magnetic space groups in a similar way.

Razvan



--
========================================
Dr. Razvan Caracas
Postdoctoral Fellow
Carnegie Institution of Washington,
Geophysical Laboratory,
5251 Broad Branch Road, N.W.
Washington DC 20015
tel: 1-202-478-8945
fax: 1-202-478-8901
url: http://www.gl.ciw.edu/~r.caracas/