[QE-users] Keep the symmetry during a calculation

[Carina Backtorp]

Dear all,


I have a question about symmetry and ibrav.

I have used BURAI to generate an input file for a vc-relax  calculation.

It got ibrav =1 (cubic),  which I also expected. Everything went fine and the calculation got started and running.

After a week or so, I decided to check the latest coordinates from the output file, and opened it in XCrySDen.

I don't know if you can check the symmetry in XCrySDen (please tell me how in that case), so I just used it in order to open the file and save it as a xsf-file. As BURAI can not read xsf-files, I used VESTA to open it (checked the symmetry which was Triclinic (ibrav=14) !) and saved it as a cif-file which could be opened in BURAI, and it was identified as Orthorhombic P( ibrav =8).


Questions:

1) When doing an vc-relax calculation in espresso, I expected that once the symmetry was given (ibrav=1) espresso should keep the symmetry during all the calculation. It seems to me that it is not the case. Is that correct? I use version 5.2.
2) If so, is there a way to do what I want? Keep the symmetry, and get a final structure that i still in the cubic form?

Kind regards,
Carina

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