[Pw_forum] CIF to PWSCF

[Eduardo Ariel Menendez Proupin]

Hi Ben
One problem is that the QE input files contains not only the structure, but
parameters for the quantum calculation. So, we have to edit the file, using
copy and paste when possible. The main problem is that the CIF files
contains olny the atomic coordinates that are non-equivalent by the
symmetry of tha space group of the crystal.
I use gdis (comes in Ubuntu distributions) to convert to other less
crystallographic format, like that of SIESTA. This automates the generation
of the symmetry equivalent positions that are not in the CIF. You can also
generate the coordinates using The  inconvenient is that it generates the
conventional cell, rather than the primitive cell. Then I use vim or gedit
to manully set the input file.

Linux distributions are plenty of programs for chemistry and physics. I
have seen that the babel code can read the CIF format and convert to many
more.

There is also a serious intenet option using the bilbao crystallographic
server. This tool is recognized by crystallographers in the International
Tables for Crsytallgraphy, so it is a trustable tool.
http://www.cryst.ehu.es/
There, you can use the programs TRANSTRU or STRCONVERT. What you need is to
convert the structure to the group P1, or  just 1, and this gives all the
information need to the QE input file. Then, use vim, gedit, or your
favorite editor.

This is not confortable at the begining, but at the end it is easy, and you
may consider it as one intiation ritual (one more, right).

For the case of iron, the stable crystal structure is so simple (BCC) that
you can write it with the only knowledge of the lattice constants, you do
not need the CIF. It is explained in the initial chapters of many (probably
all) solid state physics and materials science books. I suggest you read
that, otherwise you better quit using QE.
Best regards
Eduardo


Eduardo Menendez Proupin
Departamento de Química Fisica Aplicada
Facultad de Ciencias
Universidad Autónoma de Madrid
28049 Madrid, Spain
Phone: +34 91 497 6706
> 2012/10/24 Ben Palmer <benpalmer1983 at gmail.com>
>>
>> Hi,
>>
>> I'm new to pwscf and I'm trying to find the relaxed co-ordinates for an
>> Iron crystal.  I've been trying to set up the initial crystal from a cif
>> file.  Is there a way to convert from cif to the pwscf format?
>>
>> Thanks
>>
>> Be

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