[QE-users] How to recover structural parameters from QE 'vc-ralax' calculation

[Soumyadeep]

Dear Lorenzo,
   Thanks for the answer.

On 18-08-2020 20:49, Lorenzo Paulatto wrote:
>> Is it possible to recover structural parameter  > like
> 
>  a, b, c, angles
> 
> You can easily recover a, b, c and angles with pen, paper and
> eventually a pocket calculator. Please check this reference manual:
> https://onlinemschool.com/math/library/vector/angl/
> 
If the cell is non primitive then it is not possible with pen, paper and 
eventually a pocket calculator.

>> wykoff positions just like Rietveld fitting) after geometry 
>> optimization in Quantum espresso?
> 
> wyckoff positions remain the same before and after relax. If the
> position includes one or more free parameters, they will probably
> change, but they are very straightforward to recover from the atomic
> positions.
> 

Wwykoff positions will change during vc-relax with cell_dofree='all', 
atleast in my cases. I don't think that recovering wykoff positions are 
very straightforward from the atomic positions. It will not look like 
Rietveld fitted table specially where the cell is non-primitive. Then, 
how to make a .cif file with these converged lattice parameters?

with many thanks and best regards
Soumyadeep

> cheers
> 
>>     vc-relax output only gives CELL_PARAMETERS and all 
>> ATOMIC_POSITIONS.
>> 
>> with many thanks and best regards
>> Soumyadeep
>> -------------------------------------------------------------------
>> Soumyadeep Ghosh,
>> Senior Research Fellow,
>> Homi Bhabha National Institute (HBNI),
>> Raja Ramanna Centre for Advanced Technology, Indore, India-452013
>> Mob: (+91)9424664553
>> User Lab: 0731244-2580
>> Email: soumyadeepghosh35 at gmail.com, soumyadeep at rrcat.gov.in
>> -------------------------------------------------------------------
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Soumyadeep Ghosh,
Senior Research Fellow,
Homi Bhabha National Institute (HBNI),
Raja Ramanna Centre for Advanced Technology, Indore, India-452013
Mob: (+91)9424664553
User Lab: 0731244-2580
Email: soumyadeepghosh35 at gmail.com, soumyadeep at rrcat.gov.in
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