[QE-users] NEB calculation

[mehrdad zamzamian]

yes, i do i did scf calculation. i obtained the relaxation position of the
atoms in 2 conditions (first case before migration and the last case after
the vacancy reached to its position). i also obtained the formation energy
of the vacancy.

Best regards
S.M.Zamzamian
e-mail: mehrdad.zamzamian at gmail.com
Iran, Tehran
Sharif University of Technology

On Tue, Sep 17, 2019 at 3:04 PM Nicola Marzari <nicola.marzari at epfl.ch>
wrote:

>
>
> Try first to do a scf calculation of a vacancy. Are you able to do that?
> A relaxation? A vacancy formation energy?
>
>                         nicola
>
>
>
>
> On 17/09/2019 09:12, mehrdad zamzamian wrote:
> > Hi all dear QE users
> > I want to calculate the vacancy migration in alpha-Fe. I defined 2by2by2
> > supercell and used NEB but i could not achieve any convergence or a
> > proper result. searching in archives did not help. at the end of this
> > message is my input and a part of the output. I tested various changes
> > like k-point, ds,  num_of_images, PP ... but nothing happened.  my first
> > image gave the result of ~300eV!!!! then i gave some error (although the
> > calculation was being run) the second image was ~180 then the third
> > image i gave ~300. i also saw the atoms in xcrysden, they collapsed
> > during the calculation!!!Is there any idea about this problem? i
> appreciate.
> > ------------------------------------------------------
> > BEGIN
> > BEGIN_PATH_INPUT
> > &PATH
> >    restart_mode      = 'from_scratch'
> >    string_method     = 'neb',
> >    nstep_path        = 50,
> >    ds                = 1.D0,
> >    opt_scheme        = "broyden",
> >    num_of_images     = 12,
> >    CI_scheme         = "no-CI",
> >    path_thr          = 0.1,
> > /
> > END_PATH_INPUT
> > BEGIN_ENGINE_INPUT
> > &CONTROL
> >    prefix         = ""
> >    pseudo_dir     = "",
> > /
> > &SYSTEM
> >      a                         =  5.69623e+00
> >      degauss                   =  1.00000e-02
> >      ecutrho                   =  2.25000e+02
> >      ecutwfc                   =  2.50000e+01
> >      ibrav                     = 1
> >      nat                       = 15
> >      nspin                     = 2
> >      ntyp                      = 1
> >      occupations               = "smearing"
> >      smearing                  = "gaussian"
> >      starting_magnetization(1) =  2.00000e-01
> > /
> > &ELECTRONS
> >    mixing_beta = 0.01
> >    conv_thr =  1.0d-8
> >    electron_maxstep=200
> > /
> > &IONS
> > /
> > ATOMIC_SPECIES
> > Fe     55.84500  Fe.pbe-nd-rrkjus.UPF
> > BEGIN_POSITIONS
> > FIRST_IMAGE
> > ATOMIC_POSITIONS (angstrom)
> > Fe      0.000000   0.000000   0.000000
> > Fe      1.424058   1.424058   1.424058
> > Fe      0.000000   0.000000   2.848116
> > Fe      1.424058   1.424058   4.272174
> > Fe      0.000000   2.848116   0.000000
> > Fe      1.424058   4.272174   1.424058
> > Fe      0.000000   2.848116   2.848116
> > Fe      1.424058   4.272174   4.272174
> > Fe      2.848116   0.000000   0.000000
> > Fe      4.272174   1.424058   1.424058
> > Fe      2.848116   0.000000   2.848116
> > Fe      4.272174   1.424058   4.272174
> > Fe      2.848116   2.848116   0.000000
> > Fe      4.272174   4.272174   1.424058
> > Fe      2.848116   2.848116   2.848116
> > LAST_IMAGE
> > ATOMIC_POSITIONS (angstrom)
> > Fe      0.000000   0.000000   0.000000
> > Fe      1.424058   1.424058   1.424058
> > Fe      0.000000   0.000000   2.848116
> > Fe      1.424058   1.424058   4.272174
> > Fe      0.000000   2.848116   0.000000
> > Fe      1.424058   4.272174   1.424058
> > Fe      0.000000   2.848116   2.848116
> > Fe      1.424058   4.272174   4.272174
> > Fe      2.848116   0.000000   0.000000
> > Fe      4.272174   1.424058   1.424058
> > Fe      2.848116   0.000000   2.848116
> > Fe      4.272174   1.424058   4.272174
> > Fe      2.848116   2.848116   0.000000
> > Fe      4.272174   4.272174   1.424058
> > Fe      4.272174   4.272174   4.272174
> > END_POSITIONS
> > K_POINTS (automatic)
> >   5 5 5 0 0 0
> > END_ENGINE_INPUT
> > END
> > ---------------------------------------
> > Best regards
> > S.M.Zamzamian
> > e-mail: mehrdad.zamzamian at gmail.com <mailto:mehrdad.zamzamian at gmail.com>
> > Iran, Tehran
> > Sharif University of Technology
> >
> > _______________________________________________
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> >
>
>
> --
> ----------------------------------------------------------------------
> Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
> Director, National Centre for Competence in Research NCCR MARVEL, EPFL
> http://theossrv1.epfl.ch/Main/Contact http://nccr-marvel.ch/en/project
>
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