[Wien] Symmetry of the supercell is not taken during initialization

[Stefaan Cottenier]

If you do not break the symmetry (by displacing an atom, by introducing 
an impurity, by adding vacuum,...) then wien2k will correctly detect 
that the same situation can be described by a smaller cell (and less 
computational effort). There is no information gain in merely increasing 
the unit cell.

If you insist doing this, you can label one or more of your atoms after 
the supercell has been generated (e.g. after x supercell, replace for 
one of the inequivalent positions the atom 'Si' by 'Si1'). If sgroup now 
preserves the number of atoms, you're done. It it still reduces the cell 
by some fraction, then label a second atom ('Si2').

Stefaan




On 18/08/2011 9:33, santu baidya wrote:
> Respected Peter Blaha sir and Wien2k users,
>                  I  want to  calculate   a supercell  and  using it I
> want to  do a  spin polarised  calculation.  Using "Supercell"  command
> I  made  a  2*1*1 supercell.  I donot need  to  have  a  vacuum or
> impurity inside  the  cell so I have not introduced them. I then plotted
> the cell in in VESTA and I got the cell that I wanted. Using the new
> generated cell  I  ran the  command 'instgen_lapw'  and it  generated
> the case.inst file.  Then I ran the 'init_lapw' command to initialise .
> But I was getting the  warning  that the multiplicity of  the atom  is
> changed:
>                                      WARNING: Mult not equal. PLEASE
> CHECK outputnn-file
>                                     WARNING: ityp not equal. PLEASE
> CHECK outputnn-file
>
> Then  It is showing that the Bravais lattice has been changed. That
> means it is not taking the  symmetry of the supercell and it is going
> back to the  symmetry of the original cell(before making supercell).
> Could you please tell me what should I do to resolve this problem.Thamks.
>                                                                                                                             Santu Baidya
>                                                                                                                              SNBNCBS, kolkata
>                                                                                                                                West bengal, India
>
>
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