CIF files

[pcpatfire]

Hi,
Is there a way using diffpy.structure to save a CIF with the correct space group instead of using 'P 1'?

[sbillinge]

Thanks for the question @pcpatfire

I am asking around about this, but I think it may be hard if symmetry breaking distortions have been introduced in the modelling. In that case we would have to run the resulting structure through a program that tries to determine space group symmetry from the coordinates.

What is your use-case? Do you just want a round-trip, so a CIF is read in, run through PDFgui/diffpy-cmi and then output without breaking symmetry? Or you want a tool that "finds" the highest new symmetry after allowing distortions?

[pcpatfire]

Thanks for your answer.
I would like to use the resulting CIF to calculate the diffraction pattern (using for instance pymatgen).

[pcpatfire]

Another simple question. Is the information stored in the spacegroup variable while reading the CIF file saved anywhere after creating the structure? Is it accessible after loadind a CIF'

[dragonyanglong]

Hi @pcpatfire , you can use the cif parser to access the spacegroup info, For example:

from diffpy.structure.parsers import p_cif
a =  p_cif.P_cif()
a.parseFile('Ni.cif')
a.spacegroup.crystal_system