[Pw_forum] vc-relax

[Niels Walet]

Hi Asa,
In your file look for
  End of BFGS Geometry Optimization

There you will find

CELL_PARAMETERS (alat= 13.09720000)
   1.015188156   0.003146886  -0.001173605
  -0.474181460   1.089442373   0.000805052
  -0.239311143  -0.538971673   1.306772423

ATOMIC_POSITIONS (crystal)
Cu       0.328415750   0.859385606   0.088742021
Cu       0.671584250   0.140614394   0.911257979
K        0.167018869   0.801347159   0.491937561
K        0.832981131   0.198652841   0.508062439
Na       0.168085971   0.118294975   0.909475609
Na       0.831914029   0.881705025   0.090524391
Si       0.314793931   0.174462808   0.354726705
Si       0.685206069   0.825537192   0.645273295
Si       0.340170282   0.612141486   0.777395305
Si       0.659829718   0.387858514   0.222604695
Si       0.463511734   0.290998327   0.708095658
Si       0.536488266   0.709001673   0.291904342
Si       0.066869474   0.352645648   0.221949747
Si       0.933130526   0.647354352   0.778050253
O        0.458800144   0.773027846   0.940418013
O        0.541199856   0.226972154   0.059581987
O        0.371115727   0.187080894   0.525894662
O        0.628884273   0.812919106   0.474105338
O        0.457435947   0.675332651   0.657216818
O        0.542564053   0.324667349   0.342783182
O        0.054528553   0.805280864   0.942949234
O        0.945471447   0.194719136   0.057050766
O        0.212809942   0.956933108   0.243386073
O        0.787190058   0.043066892   0.756613927
O        0.086349622   0.565431959   0.705391223
O        0.913650378   0.434568041   0.294608777
O        0.574454929   0.879442755   0.234183849
O        0.425545071   0.120557245   0.765816151
O        0.679884769   0.600273738   0.238839180
O        0.320115231   0.399726262   0.761160820
O        0.281471323   0.545887930   0.240026198
O        0.718528677   0.454112070   0.759973802
O        0.862437391   0.741701256   0.663672041
O        0.137562609   0.258298744   0.336327959
End final coordinates



     A final scf calculation at the relaxed structure.
     The G-vectors are recalculated for the final unit cell
     Results may differ from those at the preceding step.
---
Prof. Niels R. Walet                             Phone:  +44(0)1613063693
School of Physics and Astronomy         Fax:    +44(0)1613064303
The University of Manchester               Mobile: +44(0)7516622121
Manchester, M13 9PL,  UK                  room 7.7, Schuster Building
email: Niels.Walet at manchester.ac.uk
web:   http://www.theory.physics.manchester.ac.uk/~mccsnrw<../../owa/redir.aspx?C=8f9098c1943846dcba17536b8618a38a&URL=http%3a%2f%2fwww.theory.physics.manchester.ac.uk%2f%7emccsnrw>
________________________________
From: Alvaro Santos Alves [asa at uefs.br]
Sent: 09 September 2015 19:44
To: Niels Walet
Cc: pw_forum at pwscf.org
Subject: Re: [Pw_forum] vc-relax

Dear Bang and Niels. Good afternoon. First, thank you for your attention. My first message was not really very clear. Therefore, I am attaching the output file.



Álvaro Santos Alves
Universidade Estadual de Feira de Santana, Bahia, Brazil
Departamento de Física
Laboratório de Física de Materiais.

2015-09-09 11:17 GMT-03:00 Niels Walet <Niels.Walet at manchester.ac.uk<mailto:Niels.Walet at manchester.ac.uk>>:
Dear Asa,

As Bang already says, your message is not very clear on details. Normally when running vc-relax pw.x will do a final self-consistent calculation after the relaxiation has converged. You can definitely extract cell parameters at that point (positions and celldm); I have done so many times.

There is a weakness, and sometimes the code crashes at the point of doing this self-consistent calculation (when the unit/super cell has changed too much). Even at that point, you can use the final output of the code to reconstruct the positions and the cell shape. A good way to check is to use the scripts for xcrysden; the "videos" xcrysden makes are usually a very good test of the minimisation, and will show you what happens.

Niels

--
Prof. Niels R. Walet                    Phone:  +44(0)1613063693<tel:%2B44%280%291613063693>
School of Physics and Astronomy         Fax:    +44(0)1613064303<tel:%2B44%280%291613064303>
The University of Manchester            Mobile: +44(0)7516622121<tel:%2B44%280%297516622121>
Manchester, M13 9PL
Niels.Walet at manchester.ac.uk<mailto:Niels.Walet at manchester.ac.uk> http://theory.physics.manchester.ac.uk/~mccsnrw


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