[Pw_forum] Fw: visualizing structures in xcrysden

[Tone Kokalj]

On Wed, 2015-10-21 at 08:34 +0000, Jaret Qi wrote:
> 
> 
> On Wednesday, October 21, 2015 2:27 AM, Jaret Qi <jaretqi at yahoo.com>
> wrote:
> 
> 
> Hello Quantum Espresso users,
> I've got a question about visualizing a structure using xcrysden.
> From xcrysden I choose Display >>unit of repetition...>> unit cell
> but the system after relaxing looks different than before relaxing I
> mean why i do not have that box of more atoms like the unrelaxed
> case.

The reason is likely related to the fact that the atom(s) at the border
(or at the corner) moved a bit. For example in your input you may have
an atom at (0,0,0), hence you see it at every corner of the unit cell.
But if that atom moves a bit during relaxation, say to (0.1,0.05,0.03)
you will only see this particular instance, because all the (first)
periodic replicas are outside the unit cell, i.e., the ([0-1], [0-1],
[0-1]) range.

To verify that everything is correct increase stepwise the
number of displayed unit-cells and you will notice that the atoms you
considered as missing will appear.

Regards, Tone


-- 
Anton Kokalj
J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia 
(tel: +386-1-477-3523 // fax:+386-1-477-3822)

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