[Pw_forum] CPO-27-Zn scf not converge

Mon Jun 6 12:44:01 CEST 2016

And THANKS A LOT.
> Il giorno 06 giu 2016, alle ore 12:24, Paolo Giannozzi <p.giannozzi at gmail.com> ha scritto:
> 
> You need:
> - the space group number
> - the cell parameters (for the rhombohedral lattice, not the hexagonal one)
> - the Wyckoff positions. If the latter are given in hexagonal axis, as
> they are here:
>  http://www.cryst.ehu.es/cgi-bin/cryst/programs/nph-wp-list
>  use "rhombohedral=.false."
> This is all I know about the specific case of rhombohedral groups
> 
> Paolo
> 
> On Sat, Jun 4, 2016 at 8:01 PM, Lorenzo Donà <lorechimica91 at hotmail.it> wrote:
>> Dear Paolo I have tried a lot of inputs with space_group=148 keyword but the
>> structure found is incorrect…
>> Or better is correct the number of atom 54 in the cell but the position is
>> incorrect.
>> Please can you help me to understand the correct input for my system, can
>> you tell me how to create the correct structure input using the keyword
>> space_group.
>> I must tell you that i found problem only for this system for cubic or
>> ORTHORHOMBIC system I found NO problem.
>> Thanks a lot if you can help me with my problem.
>> Dearly
>> lorenzo
>> 
>> Il giorno 31 mag 2016, alle ore 21:58, Paolo Giannozzi
>> <p.giannozzi at gmail.com> ha scritto:
>> 
>> For the rhombohedral (or trigonal) trigonal lattice, cosab=-0.5 means
>> that the angle between any two of the three primitive vectors is 120,
>> that is, they lie on a plane. This is why the code complains. By the
>> way, here a converter between rhombohedral and hexagonal cells:
>> http://qpeng.org/tools/r2h.html, and here a  picture (fig.5):
>> http://xrayweb.chem.ou.edu/notes/symmetry.html
>> 
>> 
>> On Tue, May 31, 2016 at 9:57 AM, Lori 91 <lorechimica91 at hotmail.it> wrote:
>> 
>> Thanks to replay Davide.
>> cosab=-0.5 give me an error.
>> Thanks a lot dearly
>> Lorenzo
>> 
>> Inviato da iPhone
>> 
>> Il giorno 31 mag 2016, alle ore 09:16, Tiana Davide <davide.tiana at epfl.ch>
>> ha scritto:
>> 
>> Ciao Lorenzo
>> 
>> I am not sure but one problem could be that you're using cosab 0.5 (60
>> degrees) instead of cosab=-0.5 (120 degrees)
>> another one (again just a guess) is your cut-off seems to be really low even
>> for an ultrasoft pseudopotential.
>> 
>> anyway, you should try with this electron setting
>> 
>> mixing_mode='local-TF',
>> mixing_beta=0.6,
>> 
>> I've not problem in converging it (using different pseudo though)
>> 
>> Cheers
>> Davide
>> 
>> P.S. the last test you can do is to use a bit of smearing, for instance:
>> 
>> occupations='smearing',
>> smearing='marzari-vanderbilt'
>> degauss=0.05
>> ________________________________________
>> ------------------------------
>> 
>> Message: 2
>> Date: Sun, 29 May 2016 21:11:49 +0200
>> From: Lorenzo Don? <lorechimica91 at hotmail.it>
>> Subject: [Pw_forum] CPO-27-Zn scf not converge
>> To: PWSCF Forum <pw_forum at pwscf.org>
>> Message-ID: <BLU436-SMTP367637BD78842FCA03B145CB440 at phx.gbl>
>> Content-Type: text/plain; charset="us-ascii"
>> 
>> Dear all can you help me or give me some tips to make scf convergence on
>> this calculation:
>> 
>> &control
>>  pseudo_dir='/home/utente/Scaricati/espresso-5.4.0/pseudo/'
>>  outdir = './',
>>  wf_collect = .true.,
>>  verbosity= high,
>> /
>> &system
>>  ibrav=  5,
>>  a= 25.226, cosab= 0.5,  space_group = 148,
>>  nat=  9, ntyp= 4,
>>  ecutwfc =15.0,
>>  occupations='fixed', smearing='gauss',
>>   input_dft= PBE,
>> /
>> &electrons
>>  mixing_mode='plain'
>>  diagonalization='david'
>>  mixing_beta = 0.01
>>  conv_thr= 1.0e-4
>>  electron_maxstep=500,
>> /
>> ATOMIC_SPECIES
>> Zn 65.409 Zn.pbe-van.UPF
>> C 12.010  C.pbe-van_ak.UPF
>> O 16.00   O.pbe-van_ak.UPF
>> H 1.00    H.pbe-van_ak.UPF
>> ATOMIC_POSITIONS crystal_sg
>> C   7.127430447398E-02 -2.455696438145E-01  7.991093030472E-02
>> C   1.197468901477E-01 -2.066445045066E-01  2.152449225957E-01
>> C   2.117353032357E-01 -1.117780631842E-01  2.553368090727E-01
>> C   1.646071563067E-01 -1.528403540257E-01  1.440875844425E-01
>> H   1.629458066146E-01 -1.419696182443E-01 -4.760745519579E-03
>> Zn  -1.943259345214E-02  2.834354147594E-01  3.060064447988E-01
>> O   7.229455751443E-02 -2.290060932141E-01 -9.085450716092E-02
>> O   3.018234203718E-02 -2.947952345384E-01  1.422041978763E-01
>> O   2.519030126218E-01 -6.097111538485E-02  1.721974260943E-01
>> K_POINTS gamma
>> 
>> Thanks a lot to help me
>> 
>> dearly
>> 
>> lorenzo
>> 
>> 
>> 
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>> 
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>> 
>> 
>> --
>> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
>> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
>> Phone +39-0432-558216, fax +39-0432-558222
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> 
> 
> -- 
> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
> 
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