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[Martin Haeufel <martin.haeufel@googlemail.com>]

Dear Mohua Bhattacharya, dear Xavier, dear ABINIT users,

@Mohua Bhattacharya

maybe the documentation is not up-to-date. But, normally I would still
suggest to only use the documented features.

@Xavier, all ABINIT users: Question

There's another thing I would like to point out:

If you start with optcell 0 and then continue with optcell 2, you might
end up with a different crystal symmetry.

Why is that? Well, in step 1 the structure symmetry might change,
because it corresponds to energetically more favourable ionic positions.
But in step 2 the symmetry is fixed to the input symmetry, which is now
the output of step 1!

Is that correct?

Let's think about the following situation: I have a crystal structure
with correct symmetry, but I want perform (LDA+GW) calculations with a
method that differs from the one that was used for the structural
optimization (e.g. paw/uspp instead of norm-conserving pp).

Then the crystal structure should also be optimized with the new method.

Am I right?

What it is the suggested procedure in this case? So should one use
optcell 2, and nothing else? Is there a way to use less cpu-seconds?

Martin Haeufel
TU Munich, WSI (T33)
www.wsi.tum.de

Mohua Bhattacharya schrieb:
> Hi Martin,
> Thank you very much for your help. It worked. What confuses me that the
> same input file with restartxf 1 and getwfk2 1 worked for the
> optimization of a different structure with optcell 0 and optcell 1.
> Thanks again.
> Regards
> Mohua