[Pw_forum] hi, I want to ask how to construct R-3c symmetry structure?

[Axel Kohlmeyer]

On Nov 22, 2007 9:56 PM,  <r95222066 at ntu.edu.tw> wrote:
> Hello,
>      I want to ask how to construct R-3c symmetry ? I have used wien2k
> to construct
> hexegonal and rhombohedral structure on Ca3Co2O6,and I write the
> position to scf file.
> But the scf.out file appeal "no symmetry" message!!

hi!

this is no surprise. please read the INPUT_PW
file more carefully and understand the difference
between alat and cystal units of the ATOMIC_POSITIONS
section of the input.

cheers,
   axel.

> Here is my input data:
> ----------------------------------------------------------------------
> (a) Ca3Co2O6 hexagonal structure scf file
>    ibrav = 4, celldm(1) =17.1228,celldm(3)=1.1441342,
>      nat= 66, ntyp= 3,nspin=2,
> ATOMIC_POSITIONS
> Ca  0.369000  0.000000  0.250000
     Cartesian axes

[...]

>       site n.     atom                  positions (a_0 units)
>           1           Ca  tau(  1) = (   0.6190000   0.8810000   0.2500000  )
> -----------------------------------------------------------------------------
>
> Thanks for your help
>                 Bing-Hong Chen
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>



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Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
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