[Pw_forum] Geometry optimization does not converge
Gunther Jegert
guntherjegert at mytum.de
Mon Sep 21 14:56:48 CEST 2009
Dear all,
I am quite new to the PWscf community and currently I am trying to do a
geometry relaxation for a SiO2-slab with 84 atoms, where I introduced an
Oxygen vacancy. Things went pretty well for the neutral slab with vacancy.
However, when I try to charge the vacancy by removing an electron, I run
into problems. Starting from the relaxed geometry of the neutral vacancy,
the BFGS algorithm does not converge anymore. I end up with the following
error:
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
from bfgs : error # 1
bfgs history already reset at previous step
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
stopping ...
This error has been discussed several times in the forum (f. i.
(http://www.democritos.it/pipermail/pw_forum/2007-January/005834.html))and
I, of course, checked the archives for propositions how to solve the
problem. Following Stefano’s
(http://www.democritos.it/pipermail/pw_forum/2007-January/005840.html) and
Axel’s
(http://www.democritos.it/pipermail/pw_forum/2007-January/005843.html)
suggestions, I varied the energy cutoff between 40 – 60 Ry and kept the
density ten times higher. I added some additional unoccupied states and a
smearing. I also increased the conv_thr for the electrons up to 1D-11. I
even tried different starting geometries. However, I always end up with a
too high force in the order of 1D-2 (forc_conv_thr = default).
Might I still have problems with too noisy energies due to insufficient
scf-convergence or inaccurate forces or do I just have a stupid beginner’s
mistake in my input?
Below, I have added an exemplary input file. I would be grateful, if you
could have a look on it and check it. Any suggestion of you is very, very
welcome!
&CONTROL
calculation = 'relax' ,
restart_mode = 'restart' ,
outdir = '/home/PWscf/SiO2_84_Ovacp1_relax/output//' ,
pseudo_dir = '/home/PWscf/pseudo//' ,
nstep = 200 ,
/
&SYSTEM
ibrav = 0,
nat = 83,
ntyp = 3,
ecutwfc = 60 ,
ecutrho = 600 ,
nelec = 409 ,
nbnd = 220,
occupations = 'smearing' ,
degauss = 0.05 ,
smearing = 'methfessel-paxton' ,
nspin = 2 ,
/
&ELECTRONS
conv_thr = 1.D-9 ,
mixing_beta = 0.1 ,
mixing_mode = 'local-TF' ,
mixing_ndim = 10 ,
/
&IONS
ion_dynamics = 'bfgs' ,
pot_extrapolation = 'second_order' ,
wfc_extrapolation = 'second_order' ,
/
CELL_PARAMETERS hexagonal
17.414330330 6.200601079 0.000000000
0.000000000 13.777142870 0.000000000
0.000000000 0.000000000 42.588738040
ATOMIC_SPECIES
O 15.99900 O.pbe-van_bm.UPF
Si 28.08600 Si.pbe-n-van.UPF
H 1.00794 H.pbe-van_bm.UPF
ATOMIC_POSITIONS crystal
H 0.442138619 0.127580299 0.242115140
H 0.896137968 0.169119175 0.231615489
H 0.145279030 0.729466154 0.185318477
H 0.568527920 0.766728712 0.198838355
H 0.457668337 0.648606147 0.882235439
H 0.943934588 0.667149402 0.882893664
H 0.230323559 0.332247876 0.847403349
H 0.718571406 0.319187862 0.839952063
O 0.364677524 0.489280841 0.306670494
O 0.867635321 0.478867163 0.284064758
O 0.147367650 0.236115994 0.598026320
O 0.649640819 0.240794516 0.584731050
O 0.006278921 0.852123145 0.451026193
O 0.505597281 0.853373705 0.451280302
O 0.272809908 0.659725422 0.767916947
O 0.779049125 0.652527075 0.765357869
O 0.012328673 0.412490052 0.389290845
O 0.531224781 0.403102299 0.404465186
O 0.301626474 0.205319075 0.698724798
O 0.781065101 0.224772715 0.689991966
O 0.399409099 0.024956692 0.247297497
O 0.872257458 0.051528049 0.239846197
O 0.165316856 0.807508121 0.552180617
O 0.674267803 0.814813814 0.545851753
O 0.371769306 0.230668120 0.470840104
O 0.874075269 0.237128242 0.461296955
O 0.140604238 0.045485854 0.762585096
O 0.636783689 0.032316531 0.746475796
O 0.227654885 0.869784726 0.305080065
O 0.732727431 0.858504650 0.301584259
O 0.016547404 0.618236231 0.612079200
O 0.499871866 0.635111488 0.584920922
O 0.352145267 0.087370571 0.364285089
O 0.869168592 0.063942036 0.358940555
O 0.147949565 0.833154474 0.667584191
O 0.651280724 0.772724044 0.662149348
O 0.227434967 0.645403363 0.208182128
O 0.662565566 0.668667284 0.208416304
O 1.017204746 0.453226494 0.506583053
O 0.136606701 0.247643881 0.288287407
O 0.625203555 0.236268317 0.300390560
O 0.422870566 0.005178966 0.601178945
O 0.910961373 -0.002707092 0.599445140
O 0.049445293 0.422821214 0.745842272
O 0.533616582 0.415059161 0.741837098
O 0.279059613 0.620877043 0.456332047
O 0.772220558 0.616326195 0.445880739
O 0.077686441 0.628262425 0.307134784
O 0.592714281 0.614412248 0.320651893
O 0.355511589 0.386483961 0.603007628
O 0.861212384 0.386623507 0.596590250
O 0.217865803 0.001430950 0.458554135
O 0.719084261 0.003380876 0.451700786
O -0.012841619 0.805524587 0.760936012
O 0.491588382 0.790461355 0.759417041
O 0.491159178 0.549730308 0.851262651
O 0.986487073 0.567079624 0.852990171
O 0.287151091 0.251418691 0.815141144
O 0.774113742 0.233345538 0.808313178
Si 0.022946405 0.442457010 0.317456331
Si 0.529681143 0.438905148 0.330234749
Si 0.304976291 0.200078045 0.627530596
Si 0.808520928 0.210558149 0.619785676
Si 0.161464516 0.828055173 0.481008952
Si 0.671356418 0.820865731 0.473400870
Si 0.445482049 0.605073868 0.781879032
Si 0.948636471 0.613116893 0.782529738
Si 0.279447583 0.058249921 0.300110703
Si 0.777972225 0.052171461 0.299130437
Si 0.059696263 0.813964553 0.608786133
Si 0.566523466 0.812843443 0.600031241
Si 0.193805384 0.233036488 0.756882342
Si 0.681560751 0.226501789 0.748830087
Si 0.408990216 0.420762023 0.452805513
Si 0.920407319 0.429512363 0.449897638
Si 0.222030251 0.663241013 0.280168453
Si 0.713290716 0.659481955 0.277387702
Si 0.010118971 0.426126379 0.578196606
Si 0.500224259 0.418800498 0.580296470
Si 0.362955019 0.035259574 0.433753945
Si 0.867091171 0.039993888 0.429863970
Si 0.137475224 0.836500083 0.740406223
Si 0.640529374 0.813508387 0.734302882
K_POINTS
2
0.2500000000000000 0.2500000000000000 0.0000000000000000
0.500000000000000
0.2500000000000000 -0.2500000000000000 0.0000000000000000
0.500000000000000
Best wishes
Gunther
_________________________________
Dipl.-Phys. Gunther Jegert
Lehrstuhl für Nanoelektronik
Technische Universität München
Gebäude N8, Raum 1820
Theresienstraße 90
80333 München
Phone: +49 89 289 25370
Mail: <mailto:bernhard.fabel at tum.de> guntherjegert at mytum.de
Web: <http://www.nano.ei.tum.de/> http://www.nano.ei.tum.de
_________________________________
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