[Pw_forum] SCF run not converging

[Paolo Giannozzi]

On Wed, Dec 14, 2016 at 3:19 PM, sayan chaudhuri <csayan895 at gmail.com>
wrote:

> It is in the second mail in this thread. Mr. Lorenzo Paulatto said the
> problem may be because the unit cell is too small.

here?

>> >> > > it looks to me like your unit cell is too small, the atoms are all
>> >> > > crumped together.

your unit cell is in fact very wrong. Have you read the following line?

>> >> > > Please note that celldm(1) is specified in atomic bohr units.

(answer: no, you haven't read it)

Paolo

>> >> > > 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
>> >> > >
>> >> > > _______________________________________________
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>> >> > > 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
>> >>
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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