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I have a other question. The cell with the zeolite alone has been optimized before. Now I am optimizing a molecule in the zeolite, so ions are allowed to move but not the cell parameters (isif=2). My problem is that the job stop with a nice message in OUTPUT:

reached required accuracy - stopping structural energy minimisation

But looking at the energy, ihave:

1 F= -.12142515E+04 E0= -.12141838E+04 dE =-.121425E+04
2 F= -.12089174E+04 E0= -.12088690E+04 d E =0.533411E+01
3 F= -.12133120E+04 E0= -.12133120E+04 d E =0.939439E+00
4 F= -.12139585E+04 E0= -.12139585E+04 d E =0.293020E+00
5 F= -.12140957E+04 E0= -.12140957E+04 d E =0.155805E+00
6 F= -.12140990E+04 E0= -.12140990E+04 d E =0.152529E+00
7 F= -.12142965E+04 E0= -.12142965E+04 d E =-.197559E+00
8 F= -.12144783E+04 E0= -.12144783E+04 d E =-.379328E+00
9 F= -.12138631E+04 E0= -.12138631E+04 dE =0.615193E+00
10 F= -.12145721E+04 E0= -.12145716E+04 dE =-.938001E-01
11 F= -.12162551E+04 E0= -.12161984E+04 dE =-.168299E+01
12 F= -.12146256E+04 E0= -.12146256E+04 dE =-.535421E-01
13 F= -.12146294E+04 E0= -.12146294E+04 dE =-.572786E-01
14 F= -.12146933E+04 E0= -.12146933E+04 dE =-.639359E-01
15 F= -.12146591E+04 E0= -.12146591E+04 dE =-.297472E-01
16 F= -.12146653E+04 E0= -.12146653E+04 dE =-.359406E-01
17 F= -.12146585E+04 E0= -.12146585E+04 dE =0.680333E-02
18 F= -.12146778E+04 E0= -.12146778E+04 dE =-.125125E-01
19 F= -.12146820E+04 E0= -.12146820E+04 dE =-.420113E-02
20 F= -.12146944E+04 E0= -.12146944E+04 dE =-.165427E-01
21 F= -.12146865E+04 E0= -.12146856E+04 dE =0.782720E-02
22 F= -.12184061E+04 E0= -.12183572E+04 dE =-.371172E+01
23 F= -.12146887E+04 E0= -.12146887E+04 dE =0.566615E-02
24 F= -.12146855E+04 E0= -.12146854E+04 dE =0.886161E-02
25 F= -.12146920E+04 E0= -.12146920E+04 dE =0.235241E-02
26 F= -.12157709E+04 E0= -.12157162E+04 dE =-.107894E+01
27 F= -.12174993E+04 E0= -.12174439E+04 dE=-.280724E+01
28 F= -.12146810E+04 E0= -.12146810E+04 dE=0.110042E-01


and the forces are:

FORCES: max atom, RMS 6.296283 0.954131
FORCES: max atom, RMS 8.998567 1.479871
FORCES: max atom, RMS 6.213167 0.942227
FORCES: max atom, RMS 3.793713 0.610472
FORCES: max atom, RMS 2.913586 0.450477
FORCES: max atom, RMS 2.956329 0.435797
FORCES: max atom, RMS 4.950146 0.656430
FORCES: max atom, RMS 2.158212 0.327393
FORCES: max atom, RMS 13.034069 1.432504
FORCES: max atom, RMS 1.901508 0.204131
FORCES: max atom, RMS 3.744885 0.553470
FORCES: max atom, RMS 2.025311 0.235268
FORCES: max atom, RMS 1.370555 0.166462
FORCES: max atom, RMS 2.334427 0.257160
FORCES: max atom, RMS 1.583770 0.171123
FORCES: max atom, RMS 0.933270 0.117191
FORCES: max atom, RMS 1.387691 0.183639
FORCES: max atom, RMS 0.430498 0.060396
FORCES: max atom, RMS 0.601510 0.080773
FORCES: max atom, RMS 0.458199 0.071254
FORCES: max atom, RMS 0.340981 0.055395
FORCES: max atom, RMS 6.529578 0.747447
FORCES: max atom, RMS 0.664476 0.094457
FORCES: max atom, RMS 0.556957 0.089185
FORCES: max atom, RMS 0.491018 0.076739
FORCES: max atom, RMS 3.531807 0.691398
FORCES: max atom, RMS 6.552275 0.806801
FORCES: max atom, RMS 1.583498 0.194138


So finally, I don't really understand why the calculation stops, and I doubt that the actual geometry is optimized.
What is your opinion ?

Thank you in advance,
Pierre.

PS the INCAR is:
LCHARG=.TRUE.
LWAVE=.TRUE.

ISTART=1
ICHARG=1

LREAL=Auto
PREC=Med
ENCUT=350

IBRION=2
ISIF=2
EDIFF=1E-5
EDIFFG=1E-4

IALGO=48
NELMIN=6
NSW=500

ISMEAR=0
SIGMA=0.1

your geometries do not seem to converge straightforwardly, the total energies do not steadily decrease, but oscillate from the very beginning: Maybe, the default stepwidth of the first step (POTIM=0.5) is too large for that system. I would therefore recommend to
--) decrease POTIM for the first step
--) and / or choose a different ionic optimization algorithm (like damped MD)
--) choose the forces as convergence criterium