[QE-users] Optimization does not converge

Thomas Brumme thomas.brumme at uni-leipzig.de
Thu Apr 4 14:34:06 CEST 2019


Dear Wei gui,

Adding to the things mentioned by Dominik you should think of adding
the dipole correction - even more if you want to simulate the charged
system with the hydroxy-ion.

Regards

Thomas

On 4/4/19 2:18 PM, dv009200 at fh-muenster.de wrote:
> I'm not sure but I think it has to do with the fact that you have an
> unpaired electron in your system. You haven't defined the tot_charge of
> your system, therefor the default value of tot_charge=0 means that you
> have an OH radical adsorbed/bonded to the graphene layer. If that's what
> you want you should specify nspin and tot_magnetization. If you want
> instead a hydroxy-ion (OH-) adsorbed on to the graphene layer you should
> set the tot_charge=-1.
>
> But as I said I'm not sure about this, so maybe there are some other
> suggestions from users with more experience in this area of expertise?
>
> Best Regards
>
> Dominik
>
> M.Sc. Dominik Voigt PhD Student
> Münster University of Applied Sciences
> Email: dv009200 at fh-muenster.de
>
>
>> Dear QE users,
>> I am trying to optimize a single-layer graphene connected to a hydroxyl
>> group.After 48 scf cycles,the optimization result has never reached the
>> convergence value,the force of some atoms is always greater than the
>> convergence threshold.But when I connect an epoxy group instead of a
>> hydroxyl group on the graphene sheet, the optimization can reach
>> convergence after 24 scf cycles.Does anyone know the reason for this?
>> Any suggestions would be greatly appreciated.
>> Thank you.
>>
>>
>>   &control
>>      calculation  = 'relax',
>>      prefix='QJ1GO',
>>      pseudo_dir = '/public/home/duan1/GuiWei/pseudo/',
>>      outdir='/public/home/duan1/GuiWei/tempdir/'
>>      tstress = .true.
>>      tprnfor = .true.
>>      etot_conv_thr=1.0D-4
>>      forc_conv_thr=1.0D-3
>> /
>>   &system
>>      ibrav= 0,
>>      nat=66,
>>      ntyp=3,
>>
>>      occupations='smearing',
>>      smearing='mp',
>>      degauss=0.02,
>>
>>
>>      ecutwfc =40.0
>>      ecutrho =320.0
>>
>>      vdw_corr='DFT-D'
>>      london_s6 = 0.75
>>
>>
>> /
>> &electrons
>>      conv_thr =  1.0d-8
>>      mixing_beta = 0.2
>>      mixing_mode = 'local-TF'
>>      mixing_ndim=16
>>      electron_maxstep=200
>> /
>> &IONS
>>    ion_dynamics='bfgs'
>> /
>> CELL_PARAMETERS angstrom
>> 19.680000000000003       0.000000000000010       0.000000000000000
>>   0.000000000000000       8.521689973238882       0.000000000000000
>>   0.000000000000000       0.000000000000000      25.000000000000000
>> ATOMIC_SPECIES
>> C  12.0107   C.pbe-rrkjus.UPF
>> O   16.00    O.pbe-rrkjus.UPF
>> H   1.00     H.pbe-rrkjus.UPF
>> ATOMIC_POSITIONS  crystal
>>    C   0.0000000000000000   0.0000000000000000   0.2164000000000000
>>    C   0.1250000000000000  -0.0000000000000000   0.2164000000000000
>>    C   0.0625000000000000   0.2499999999999999   0.2164000000000000
>>    C   0.0000000000000000   0.4999999999999999   0.2164000000000000
>>    C   0.2500000000000000  -0.0000000000000002   0.2164000000000000
>>    C   0.1875000000000000   0.2499999999999999   0.2164000000000000
>>    C   0.1250000000000000   0.4999999999999998   0.2164000000000000
>>    C   0.0624999999999998   0.7499999999999989   0.2164000000000000
>>    C   0.3750000000000000  -0.0000000000000002   0.2164000000000000
>>    C   0.3125000000000000   0.2500000000000000   0.2164000000000000
>>    C   0.2500000000000000   0.4999999999999999   0.2164000000000000
>>    C   0.1875000000000000   0.7499999999999989   0.2164000000000000
>>    C   0.5000000000000000  -0.0000000000000002   0.2164000000000000
>>    C   0.4375000000000000   0.2500000000000000   0.2164000000000000
>>    C   0.3750000000000000   0.4999999999999999   0.2164000000000000
>>    C   0.3125000000000000   0.7499999999999988   0.2164000000000000
>>    C   0.6250000000000000  -0.0000000000000004   0.2164000000000000
>>    C   0.5625000000000000   0.2500000000000000   0.2164000000000000
>>    C   0.5000000000000000   0.4999999999999999   0.2164000000000000
>>    C   0.4375000000000000   0.7499999999999988   0.2164000000000000
>>    C   0.7500000000000000  -0.0000000000000004   0.2164000000000000
>>    C   0.6875000000000000   0.2499999999999999   0.2164000000000000
>>    C   0.6250000000000000   0.4999999999999999   0.2164000000000000
>>    C   0.5625000000000000   0.7499999999999988   0.2164000000000000
>>    C   0.8750000000000000  -0.0000000000000004   0.2164000000000000
>>    C   0.8125000000000000   0.2499999999999990   0.2164000000000000
>>    C   0.7500000000000000   0.4999999999999999   0.2164000000000000
>>    C   0.6875000000000000   0.7499999999999989   0.2164000000000000
>>    C   0.9375000000000000   0.2499999999999990   0.2164000000000000
>>    C   0.8750000000000000   0.5000000000000000   0.2164000000000000
>>    C   0.8125000000000000   0.7499999999999988   0.2164000000000000
>>    C   0.9375000000000000   0.7499999999999988   0.2164000000000000
>>    C   0.0624999725702591   0.0833332967603452   0.2164000000000000
>>    C  -0.0000000274297411   0.3333332967603450   0.2164000000000000
>>    C   0.1874999725702590   0.0833332967603452   0.2164000000000000
>>    C   0.1249999725702590   0.3333332967603450   0.2164000000000000
>>    C   0.0624999725702589   0.5833332967603438   0.2164000000000000
>>    C  -0.0000000274297409   0.8333332967603447   0.2164000000000000
>>    C   0.3124999725702590   0.0833332967603452   0.2164000000000000
>>    C   0.2499999725702590   0.3333332967603450   0.2164000000000000
>>    C   0.1874999725702590   0.5833332967603448   0.2164000000000000
>>    C   0.1249999725702590   0.8333332967603447   0.2164000000000000
>>    C   0.4374999725702590   0.0833332967603452   0.2164000000000000
>>    C   0.3749999725702590   0.3333332967603450   0.2164000000000000
>>    C   0.3124999725702590   0.5833332967603448   0.2164000000000000
>>    C   0.2499999725702590   0.8333332967603447   0.2164000000000000
>>    C   0.5624999725702590   0.0833332967603451   0.2164000000000000
>>    C   0.4999999725702591   0.3333332967603449   0.2164000000000000
>>    C   0.4374999725702590   0.5833332967603438   0.2164000000000000
>>    C   0.3749999725702590   0.8333332967603447   0.2164000000000000
>>    C   0.6874999725702590   0.0833332967603451   0.2164000000000000
>>    C   0.6249999725702590   0.3333332967603450   0.2164000000000000
>>    C   0.5624999725702590   0.5833332967603447   0.2164000000000000
>>    C   0.4999999725702591   0.8333332967603448   0.2164000000000000
>>    C   0.8124999725702590   0.0833332967603451   0.2164000000000000
>>    C   0.7499999725702590   0.3333332967603450   0.2164000000000000
>>    C   0.6874999725702600   0.5833332967603440   0.2164000000000000
>>    C   0.6249999725702590   0.8333332967603438   0.2164000000000000
>>    C   0.9374999725702590   0.0833332967603450   0.2164000000000000
>>    C   0.8749999725702590   0.3333332967603450   0.2164000000000000
>>    C   0.8124999725702600   0.5833332967603438   0.2164000000000000
>>    C   0.7499999725702590   0.8333332967603438   0.2164000000000000
>>    C   0.9374999725702590   0.5833332967603438   0.2164000000000000
>>    C   0.8749999725702601   0.8333332967603448   0.2164000000000000
>>    O   0.5008325506691220   0.4975899051684459   0.2743438844378600
>>    H   0.4505865611121930   0.4983293698599460   0.2875531708238770
>> K_POINTS automatic
>> 2  2  1  0  0  0
>>
>>
>> Wei gui
>> School of Mechanical Engineering?Chongqing University, China
>>
>>
>>
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>
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-- 
Dr. rer. nat. Thomas Brumme
Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry
Leipzig University
Phillipp-Rosenthal-Strasse 31
04103 Leipzig

Tel:  +49 (0)341 97 36456

email: thomas.brumme at uni-leipzig.de



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