[Pw_forum] SCF run not converging
sayan chaudhuri
csayan895 at gmail.com
Wed Dec 14 15:19:28 CET 2016
It is in the second mail in this thread. Mr. Lorenzo Paulatto said the
problem may be because the unit cell is too small.
On Wed, Dec 14, 2016 at 7:45 PM, Paolo Giannozzi <p.giannozzi at gmail.com>
wrote:
> On Wed, Dec 14, 2016 at 3:00 PM, sayan chaudhuri <csayan895 at gmail.com>
> wrote:
>
> > How to get rid of the small unit cell problem?
>
> what is the "small unit cell problem"?
>
> Paolo
> > When it is a pure system, Wycoff positions with Atomic positions card
> set
> > at alat works. So, is there any definite procedure to give the position
> of
> > the atoms in the system when I am doping in the system?
> >
> > Thanking you,
> > Sayan Chaudhuri
> >
> > On Fri, Dec 9, 2016 at 7:07 PM, Lorenzo Paulatto
> > <lorenzo.paulatto at impmc.upmc.fr> wrote:
> >>
> >> It may be difficult to converge LDA+U calculations in general, starting
> >> with
> >> initial magnetizations that aren't absurd may help
> >>
> >> hth
> >>
> >> On Friday, December 9, 2016 5:29:01 PM CET Максим Арсентьев wrote:
> >> > Dear Lorenzo,
> >> >
> >> > I have the same problem - cannot achieve SCF convergence. I use higher
> >> > ecutwfc = 39.0, ecutrho = 300 but not coverging.
> >> >
> >> > Regards, Maxim Arsentev.
> >> >
> >> > 2016-12-09 12:52 GMT+04:00 Lorenzo Paulatto
> >> > <lorenzo.paulatto at impmc.upmc.fr>
> >> > > Dear Sayan,
> >> > > it looks to me like your unit cell is too small, the atoms are all
> >> > > crumped
> >> > > together. Please note that celldm(1) is specified in bohr atomic
> >> > > units.
> >> > >
> >> > > Also:
> >> > > 1. a cutoff of 30Ry is probably very small for BHS pseudopotentials
> >> > > 2. ecutrho=default (4*ecutwfc ) is probably not enough for all the
> >> > > ultrasoft
> >> > > pseudopotentials you are using
> >> > >
> >> > > I would recommend you first spend some time reproducin the
> >> > > single-element
> >> > > metal, and once you can correctly reproduce geometry, band
> structure,
> >> > > physical
> >> > > properties, you move to simulating the alloy.
> >> > >
> >> > > HTH
> >> > >
> >> > > On Friday, December 9, 2016 1:59:44 PM CET sayan chaudhuri wrote:
> >> > > > Hi,
> >> > > >
> >> > > > I am running QE self - consistently for my heusler
> alloy(Fe2TiSn)
> >> > > >
> >> > > > system, where 25% of Sn were replaced by Sb. But after 800
> >> > > > iterations
> >> > > > and
> >> > > > almost 3 hours of running also still it is not converged.
> >> > > > The code I am using is added bellow. Please tell me what is the
> >> > > > source
> >> > > > of
> >> > > > error.
> >> > > >
> >> > > > Thanking you,
> >> > > >
> >> > > > Sayan Chaudhuri
> >> > > >
> >> > > > *&control prefix='fts', calculation = 'scf', verbosity =
> >> > > > 'low', pseudo_dir = '/home/ltp/Desktop/espresso-5.
> 4.0/pseudo',
> >> > > > outdir = './tmp', / &system ibrav=2 celldm(1)=11.43,
> >> > > > nat=16, ntyp=4, nspin=2, ecutwfc=30.0,
> >> > > > starting_magnetization(1) = 0.0, starting_magnetization(2) =
> >> > > > 0.0,
> >> > > > starting_magnetization(3) = 0.5, starting_magnetization(3) =
> >> > > > 0.0,
> >> > > > occupations='tetrahedra', / &electrons electron_maxstep =
> >> > > > 3000,
> >> > > > diagonalization = 'david', mixing_mode = 'plain', conv_thr =
> >> > > > 1e-8,
> >> > > > mixing_beta=0.1, /ATOMIC_SPECIES Sb 121.76 Sb.pz-bhs.UPF Sn
> >> > > > 118.71 Sn.pz-dn-rrkjus_psl.0.2.UPF Fe 55.845
> >> > > > Fe.pz-sp-van_ak.UPF
> >> > > > Ti 47.867 Ti.pz-sp-van.UPFATOMIC_POSITIONS {crystal} Sb
> >> > > > 0.000000000 0.000000000 0.000000000 Sn
> >> > > > 0.000000000 0.500000000 0.500000000 Sn
> >> > > > 0.500000000 0.000000000 0.500000000 Sb
> >> > > > 0.500000000 0.500000000 0.000000000 Fe
> >> > > > 0.250000000 0.250000000 0.250000000 Fe
> >> > > > 0.750000000 0.750000000 0.750000000 Fe
> >> > > > 0.750000000 0.750000000 0.250000000 Fe
> >> > > > 0.250000000 0.250000000 0.750000000 Fe
> >> > > > 0.750000000 0.250000000 0.750000000 Fe
> >> > > > 0.250000000 0.750000000 0.250000000 Fe
> >> > > > 0.250000000 0.750000000 0.750000000 Fe
> >> > > > 0.750000000 0.250000000 0.250000000 Ti
> >> > > > 0.500000000 0.500000000 0.500000000 Ti
> >> > > > 0.500000000 0.000000000 0.000000000 Ti
> >> > > > 0.000000000 0.500000000 0.000000000 Ti
> >> > > > 0.000000000 0.000000000 0.500000000 K_POINTS
> >> > > > {automatic}
> >> > > > 2 2 2 0 0 0*
> >> > >
> >> > > --
> >> > > Dr. Lorenzo Paulatto
> >> > > IdR @ IMPMC -- CNRS & Université Paris 6
> >> > > phone: +33 (0)1 44275 084 / skype: paulatz
> >> > > www: http://www-int.impmc.upmc.fr/~paulatto/
> >> > > mail: 23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris
> >> > > Cédex 05
> >> > >
> >> > > _______________________________________________
> >> > > Pw_forum mailing list
> >> > > Pw_forum at pwscf.org
> >> > > http://pwscf.org/mailman/listinfo/pw_forum
> >>
> >>
> >> --
> >> Dr. Lorenzo Paulatto
> >> IdR @ IMPMC -- CNRS & Université Paris 6
> >> phone: +33 (0)1 44275 084 / skype: paulatz
> >> www: http://www-int.impmc.upmc.fr/~paulatto/
> >> mail: 23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex
> 05
> >>
> >> _______________________________________________
> >> Pw_forum mailing list
> >> Pw_forum at pwscf.org
> >> http://pwscf.org/mailman/listinfo/pw_forum
> >
> >
> >
> > _______________________________________________
> > Pw_forum mailing list
> > Pw_forum at pwscf.org
> > http://pwscf.org/mailman/listinfo/pw_forum
>
>
>
> --
> 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
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20161214/6fcc66ef/attachment.html>
More information about the users
mailing list