[QE-users] vc-relax Convergence problem with 'TS' VdW correction
Paolo Giannozzi
p.giannozzi at gmail.com
Sun Oct 14 13:40:13 CEST 2018
Answering myself: it's the combination "variable cell +
Tkatchenko-Scheffler" that doesn't work properly
PG
On Sat, Oct 13, 2018 at 6:46 PM Paolo Giannozzi <p.giannozzi at gmail.com>
wrote:
> I don't think a tighter convergence threshold will fix the problem here:
> there is a mismatch between forces and energies. This calculation uses
> - Tkatchenko-Scheffler corrections
> - in a spin-polarized case
> - in a variable-cell calculation
> Assuming that there is no problem without TS, it would be helpful to know
> whether the problem is due to spin polarization, to variable cell, to both,
> or to none.
>
> PG
>
>
> On Fri, Oct 12, 2018 at 9:32 PM Nicola Marzari <nicola.marzari at epfl.ch>
> wrote:
>
>>
>> First I would try to have a much, much tighter convergence threshold
>> than conv_thr = 1.0d-6; I think we use as a standard 0.2d-9 times
>> the number of atoms - so in your case 4.0d-9, rather than
>> 1.0d-6. If your selfconsistency is poor, your forces are noisy, and the
>> relaxation slow.
>>
>> I also note that there is a variable called
>> ts_vdw_econv_thr ; not sure what it does, but seems relevant.
>>
>> nicola
>>
>>
>>
>>
>> On 12/10/2018 16:36, Hooman Yaghoobnejad Asl wrote:
>> > Dear all,
>> > I'm experiencing a problem with total force minimization when
>> > the vdw_corr = 'TS' is used. Without the vdw_corr option, force
>> > minimization completes smoothly, as shown below:
>> >
>> > Total force = 0.144455 Total SCF correction = 0.002938
>> > Total force = 0.096620 Total SCF correction = 0.004258
>> > Total force = 0.023833 Total SCF correction = 0.000694
>> > Total force = 0.013572 Total SCF correction = 0.000196
>> > Total force = 0.013176 Total SCF correction = 0.000775
>> > Total force = 0.013520 Total SCF correction = 0.001316
>> > Total force = 0.013322 Total SCF correction = 0.000670
>> > Total force = 0.013164 Total SCF correction = 0.000897
>> > Total force = 0.013634 Total SCF correction = 0.000800
>> > Total force = 0.016822 Total SCF correction = 0.000639
>> > Total force = 0.015558 Total SCF correction = 0.000354
>> > Total force = 0.012359 Total SCF correction = 0.000858
>> > Total force = 0.009014 Total SCF correction = 0.000322
>> > Total force = 0.007140 Total SCF correction = 0.000338
>> > Total force = 0.006073 Total SCF correction = 0.000556
>> > Total force = 0.005047 Total SCF correction = 0.000465
>> > Total force = 0.004639 Total SCF correction = 0.000050
>> > Total force = 0.003113 Total SCF correction = 0.000382
>> > Total force = 0.002225 Total SCF correction = 0.000268
>> > Total force = 0.001698 Total SCF correction = 0.000156
>> > Total force = 0.001505 Total SCF correction = 0.000372
>> > Total force = 0.001422 Total SCF correction = 0.000244
>> > Total force = 0.001442 Total SCF correction = 0.000420
>> > However, after implementing the VdW correction, it seems that the
>> forces
>> > cannot be minimized further even after 200 ionic steps:
>> >
>> > Total force = 0.146620 Total SCF correction = 0.003488
>> > Total force = 0.108842 Total SCF correction = 0.004843
>> > Total force = 0.069519 Total SCF correction = 0.000923
>> > Total force = 0.016339 Total SCF correction = 0.002655
>> > Total force = 0.015353 Total SCF correction = 0.001041
>> > Total force = 0.016188 Total SCF correction = 0.000361
>> > Total force = 0.016350 Total SCF correction = 0.000832
>> > Total force = 0.015878 Total SCF correction = 0.001654
>> > Total force = 0.016273 Total SCF correction = 0.000560
>> > Total force = 0.016349 Total SCF correction = 0.000406
>> > Total force = 0.015879 Total SCF correction = 0.001403
>> > .
>> > .
>> > .
>> > .
>> > Total force = 0.015866 Total SCF correction = 0.001214
>> > Total force = 0.016279 Total SCF correction = 0.000263
>> > Total force = 0.016351 Total SCF correction = 0.000394
>> > Total force = 0.015879 Total SCF correction = 0.000394
>> > Total force = 0.016277 Total SCF correction = 0.001323
>> > Total force = 0.016347 Total SCF correction = 0.000194
>> > Total force = 0.015878 Total SCF correction = 0.000606
>> > I was wondering if anyone can make a comment on this? I'm using QE 6.2
>> > on a cluster. Input copied below:
>> > &CONTROL
>> > title = 'Li0.5NiO2 NCPP FM VdW ' ,
>> > calculation = 'vc-relax' ,
>> > max_seconds = 86300 ,
>> > ! wf_collect = .true. ,
>> > outdir = '/' ,
>> > wfcdir = '/' ,
>> > pseudo_dir = '/scratch/05246/pseudo/' ,
>> > !restart_mode = 'restart' ,
>> > prefix = 'LNO' ,
>> > disk_io = 'low' ,
>> > verbosity = 'high' ,
>> > nstep = 200 ,
>> > /
>> > &SYSTEM
>> > ibrav = 0,
>> > celldm(1) = 1.889726,
>> > nat = 21,
>> > ntyp = 3,
>> > ecutwfc = 80 ,
>> > ecutrho = 320 ,
>> > occupations = 'smearing' ,
>> > degauss = 0.001 ,
>> > smearing = 'gaussian' ,
>> > nspin = 2 ,
>> > starting_magnetization(1) = 0.25,
>> > vdw_corr = 'TS' ,
>> > /
>> > &ELECTRONS
>> > electron_maxstep = 500,
>> > conv_thr = 1.0d-6 ,
>> > /
>> > &IONS
>> > /
>> > &CELL
>> > /
>> > CELL_PARAMETERS {alat}
>> > 5.790000 0.000000 0.000000
>> > -1.447500 2.507144 0.000000
>> > 0.000000 0.000000 14.221000
>> > ATOMIC_SPECIES
>> > Ni 58.69000 Ni_ONCV_PBE-1.0.upf
>> > O 15.99000 O_ONCV_PBE-1.0.upf
>> > Li 6.94000 Li_ONCV_PBE-1.0.upf
>> > ATOMIC_POSITIONS crystal
>> > O 0.000000 0.000000 0.232000
>> > O 0.000000 0.000000 0.768000
>> > O 0.333333 0.333333 0.565333
>> > O 0.333333 0.333333 0.101333
>> > O 0.166667 0.666667 0.898667
>> > O 0.166667 0.666667 0.434667
>> > Ni 0.000000 0.000000 0.500000
>> > Ni 0.333333 0.333333 0.833333
>> > Ni 0.166667 0.666667 0.166667
>> > Li 0.166667 0.666667 0.666667
>> > O 0.500000 0.000000 0.232000
>> > O 0.500000 0.000000 0.768000
>> > O 0.833333 0.333333 0.565333
>> > O 0.833333 0.333333 0.101333
>> > O 0.666667 0.666667 0.898667
>> > O 0.666667 0.666667 0.434667
>> > Ni 0.500000 0.000000 0.500000
>> > Ni 0.833333 0.333333 0.833333
>> > Ni 0.666667 0.666667 0.166667
>> > Li 0.500000 0.000000 0.000000
>> > Li 0.833333 0.333333 0.333333
>> > K_POINTS automatic
>> > 4 8 2 0 0 0
>> >
>> > Thank you
>> > P.S. I benchmarked the wf cut-off energy vs binary oxides for each
>> metal
>> > and 80 Ry gave values comparable to 320 Ry.
>> >
>> > --
>> > *Hooman Yaghoobnejad
>> > *
>> > *PhD, Department of Chemistry
>> > *
>> > *Missouri University of Science and Technology
>> > *
>> > *Rolla, MO 65409
>> > *
>> > *USA*
>> >
>> >
>> > _______________________________________________
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>> > users at lists.quantum-espresso.org
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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
>> _______________________________________________
>> users mailing list
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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
>
>
--
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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