[Pw_forum] CPO-27-Zn scf not converge

Mon Jun 6 12:50:19 CEST 2016

Dear Lorenzo Dona,

Perhaps you could try to use a visualization software to verify the
structure and export it in .xyz format. You could use VESTA to make the
structure and visualize it. VESTA can read Wyckoff positions. Furthermore,
it can export the positions of the atoms in .xyz format. You can use the
coordinates of the .xyz file as input. This way, you avoid using
space_group and crystal_sg.

Dae Kwang Jun

On Mon, Jun 6, 2016 at 7:24 PM, Paolo Giannozzi <p.giannozzi at gmail.com>
wrote:

> 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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> >
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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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