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 <[email protected]> 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 <[email protected]> > 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* >> > >> > >> > _______________________________________________ >> > users mailing list >> > [email protected] >> > https://lists.quantum-espresso.org/mailman/listinfo/users >> > >> >> >> -- >> ---------------------------------------------------------------------- >> 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 >> [email protected] >> https://lists.quantum-espresso.org/mailman/listinfo/users > > > > -- > 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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