[Pw_forum] ibrav=13

Stefano de Gironcoli degironc at sissa.it
Sat Feb 14 00:29:36 CET 2009


In pwscf you need to specify the position of all the atoms in the 
primitive unit cell of your Bravais lattice as it is defined by three 
Bravais lattice vectors  (printed at the beginning of the output of any 
run).
Coordinates are given using the ATOMIC_POSITIONS card...
Pay attention that if you are using the default format (alat), positions 
are given in cartesian coordinates in unit of alat(=celldm(1)).
If you want to use crystal coordinates (that is fractions of the BL 
vectors) you should use the following syntax
ATOMIC_POSITION crystal

hope this helps,
 stefano

Adrian wrote:
> Dear All,
>
> I would greatly appreciate some help with using ibrav=13. Does it 
> require the coordinates in the conventional unit cell or those 
> corresponding to the primitive? No matter what I've tried it just 
> doesn't seem to be right.
> Many thanks,
> Adrian
> Newcastle University
> Chem Eng. & Advanced Materials
> UK
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