Hi Pascal,
When I first started using QE 6.0 not long ago I had trouble using
crystal_sg, I suppose you have the Wyckoff positions of your atoms. What I did
was use the VESTA program which allows you to input Wyckoff positions and it
will correctly generate the cell as long as other options are correct. I then
exported to an xyz file and converted the coordinates in angstroms to internal
crystal coordinates ('crystal' option) using:
https://en.wikipedia.org/wiki/Fractional_coordinates
Fractional coordinates -
Wikipedia<https://en.wikipedia.org/wiki/Fractional_coordinates>
en.wikipedia.org
In crystallography, a fractional coordinate system is a coordinate system in
which the edges of the unit cell are used as the basic vectors to describe the
positions ...
Which worked perfectly for me. This is easily done with a Python script or
something similar!
Kindest regards,
Louis
________________________________
From: [email protected] <[email protected]> on behalf of
Pascal Boulet <[email protected]>
Sent: 23 February 2017 07:56:16
To: PWSCF Forum
Subject: [Pw_forum] Symmetry recognition
Dear all,
I am running a structural optimization with QE 6.0. The structure is
orthorhombic, ibrav=8, with 8 symmetry elements. The first run did not converge
so I have to restart it. But as I restart it, the number of symmetry is now 4,
there is a descent of symmetry. I shall say that I use the space_group option
with COORDINATES crystal_sg. But the problem remains if I put all the
coordinates (unsurprisingly).
Is there a reason for this, and can I avoid this?
Thank you
Best regards
Pascal
-
Pascal Boulet - MCF HDR, Resp. L2 MPCI - DEPARTEMENT CHIMIE
Aix-Marseille Université - ST JEROME - Avenue Escadrille Normandie Niemen -
13013 Marseille
Tél: +33(0)4 13 55 18 10 - Fax : +33(0)4 13 55 18 50
Site :
http://madirel.univ-amu.fr/pages_web_BOULET_PASCAL/annuaire<http://amu.fr/pages_web_BOULET_PASCAL/annuaire>
- Email : [email protected]<mailto:[email protected]>
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