[gpaw-users] convergence issue with spin-polarised system

[Ask Hjorth Larsen]

Good to hear, thanks.

Regards
Ask

2013/11/19 Chengjun Jin <chej at fysik.dtu.dk>:
> Hi All,
>
> Just a little feedback.
>
> By using smaller mixing like 0.05 does improve the convergence.
>
> Regards,
> Chengjun
>
> ________________________________________
> From: Ask Hjorth Larsen [asklarsen at gmail.com]
> Sent: Saturday, November 16, 2013 6:40 PM
> To: Chengjun Jin
> Cc: gpaw-users
> Subject: Re: [gpaw-users] convergence issue with spin-polarised system
>
> Hello Chengjun
>
> I think GPAW's mixers do not handle spin all that well.  The total
> magnetic moment, even in the first step which converges, is still
> changing rather significantly.  It is slightly strange that the
> calculations is considered to have converged.
>
> Try a more careful MixerSum(0.06, 5, 100.0) or so.
>
> If this won't work you can perhaps use a higher Fermi temperature.  As
> long as you are doing geometry optimization this is probably less
> critical than it would be for a binding energy calculation.
>
> (Consider parallelizing more over k-points, e.g. parallel={'domain':
> (1, 2, 2), 'band': 1}.  In future versions you can do e.g.
> parallel={'kpt': 8}.)
>
> Best regards
> Ask
>
> 2013/11/16 Chengjun Jin <chej at fysik.dtu.dk>:
>> Dear All,
>>
>> I am trying to run a spin-polarised system, a slab with NO molecule on top. I have difficulty to converge the electroinic SCF loop.
>> Attached are the traj and the output files.
>>
>> Any suggestion is apprecitated.
>>
>>
>>
>> The input files is below.
>>
>>   8 import numpy as np
>>   9 from ase.visualize import view
>>  10 from ase.io import read, write
>>  11 from ase.optimize import QuasiNewton
>>  12 from gpaw import GPAW, Mixer, MixerSum, FermiDirac
>>  13 from ase.constraints import FixAtoms
>>  14
>>  15
>>  16 system=read('scat.traj')
>>  17 #initial_magnetic_moments on N and O is(0.6, 0.4)
>>  18 system.set_pbc(111)
>>  19 #view(system)
>>  20
>>  21 calc = GPAW(
>>  22            mode='lcao',
>>  23            basis={'Au':'dzp',  'O':'dzp','N':'dzp' }, #XXX
>>  24            h=0.2,
>>  25            xc='PBE',
>>  26            kpts=(6,6,1),
>>  27            occupations=FermiDirac(width=0.1),
>>  28            txt='scat.out',
>>  29            mixer=MixerSum(),
>>  30            maxiter=1000,
>>  31            usesymm=True
>>  32            )
>>  33
>>  34 system.set_calculator(calc)
>>  35
>>  36 relax = QuasiNewton(system, trajectory= 'qn_scat.traj', logfile='qn_scat.log')
>>  37 relax.run(fmax=0.01)
>>
>>
>>
>>
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