[QE-users] QE automatically converge centered cell to primitive ?

[Paolo Giannozzi]

... and if you DO NOT supply the structure and atomic positions via the
space group and Wyckoff positions, QE generates the structure you
specified, not necessarily the one you wanted or expected :-)

Paolo

On Thu, Dec 23, 2021 at 10:25 AM Paolo Giannozzi <p.giannozzi at gmail.com>
wrote:

> I am not sure I understand what you mean. If you supply the structure and
> atomic positions via the space group and Wyckoff positions, QE generates
> the primitive (smallest) unit cell and corresponding lattice. QE does not
> change the symmetry or the structure by its own will, unless there is a bug
> for your specific case. If you prefer the so-called "conventional" unit
> cell, you need to consider the atoms that are in the conventional unit cell
> but not in the primitive one.
>
> Paolo
>
> On Wed, Dec 22, 2021 at 5:07 PM Michal Husak <Michal.Husak at vscht.cz>
> wrote:
>
>> Hi
>>
>> We had entered inside QE a structure described by fractional
>> coordinates (asymmetric unit cell)
>> and space group (C 2/c ) ....
>>  From the output we see QE had itself transformed the structure to
>> another space group and unit cell
>> (probably P 2/c  triclinic system) to get speed  of calculation ....
>>
>> Question:
>> - does QE anywhere mention, this transformation was done ?
>> - does it anywhere give the used transformation matrix ?
>>
>> We simply need to reconstruct from the QE the atom positions
>> corresponding to the original CIF data ....
>>
>> Michal Husak
>> UCT Prague
>>
>>
>>
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>
>
> --
> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
> Univ. Udine, via delle Scienze 206, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>

-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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