Dear all,
I am running a standard ionic relaxation with energy criterion set to EDIFFG=0.0001:
grep "EDIFFG" OUTCAR
EDIFFG = 0.1E-03 stopping-criterion for IOM
However, the calculation runs only 3 steps, after which the energy is far from being converged:
grep "free e" OUTCAR
free energy TOTEN = -164.41539396 eV
free energy TOTEN = -164.64088673 eV
free energy TOTEN = -164.73168408 eV
From my OUTCAR I see:
FREE ENERGIE OF THE ION-ELECTRON SYSTEM (eV)
---------------------------------------------------
free energy TOTEN = -164.73168408 eV
energy without entropy= -164.74664595 energy(sigma->0) = -164.73667137
d Force = 0.1076427E+00[ 0.947E-02, 0.206E+00] d Energy = 0.9079735E-01 0.168E-01
d Force = 0.3889362E+02[ 0.376E+02, 0.401E+02] d Ewald = 0.3885351E+02 0.401E-01
--------------------------------------------------------------------------------------------------------
POTLOK: cpu time 0.5709: real time 0.5706
--------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------
reached required accuracy - stopping structural energy minimisation
However, I don't think it reached the required accuracy. Why is it stopping?
Thanks for any hints,
David
Stopping ionic relaxation
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dholec
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alex
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Re: Stopping ionic relaxation
Hi dholec,
please check the forces section in your OUTCAR. Maybe you'll get more hints from there.
Hth,
alex
please check the forces section in your OUTCAR. Maybe you'll get more hints from there.
Hth,
alex
-
dholec
- Newbie
- Posts: 10
- Joined: Wed Nov 12, 2008 4:26 pm
- License Nr.: 584
Re: Stopping ionic relaxation
Hi Alex,
Thanks for your reply.
Firstly, I don't think the forces should matter since I am using the energy criterion for convergence (EDIFFG = 0.1E-03).
However, checking the forces after the last ionic step (after which VASP ends saying that the convergence was reached) is:
FORCES acting on ions
electron-ion (+dipol) ewald-force non-local-force convergence-correction
-----------------------------------------------------------------------------------------------
0.327E+02 0.579E+01 0.698E+01 -.355E+02 -.530E+01 -.697E+01 0.279E+01 -.494E+00 -.659E-02 -.133E-04 0.127E-04 -.141E-04
0.207E+02 0.245E+02 0.643E+01 -.216E+02 -.271E+02 -.642E+01 0.967E+00 0.267E+01 -.677E-02 0.198E-04 0.355E-05 0.158E-04
-.116E+02 -.275E+02 0.948E+01 0.135E+02 0.297E+02 -.948E+01 -.183E+01 -.216E+01 -.161E-02 0.671E-04 -.917E-04 -.156E-03
-.298E+02 0.473E+01 0.134E+02 0.325E+02 -.423E+01 -.135E+02 -.278E+01 -.500E+00 0.450E-02 -.927E-04 0.923E-04 -.421E-03
0.803E+00 -.930E+00 0.703E+01 -.804E+00 0.930E+00 -.702E+01 0.301E-02 -.638E-03 -.821E-02 -.117E-04 0.210E-04 -.135E-04
0.977E+01 -.299E+02 0.657E+01 -.116E+02 0.321E+02 -.656E+01 0.182E+01 -.217E+01 -.625E-02 -.219E-05 -.704E-05 0.141E-04
-.299E+01 -.584E+00 0.955E+01 0.301E+01 0.593E+00 -.955E+01 -.101E-01 -.617E-03 -.551E-02 0.916E-04 -.960E-05 -.156E-03
-.215E+02 0.220E+02 0.795E+01 0.225E+02 -.247E+02 -.795E+01 -.970E+00 0.266E+01 -.761E-03 -.381E-05 0.611E-04 -.610E-04
0.308E+01 -.263E+02 0.965E+01 -.309E+01 0.292E+02 -.966E+01 0.118E-01 -.293E+01 -.197E-03 -.134E-03 0.363E-04 -.182E-03
-.386E+01 -.304E+01 0.653E+01 0.447E+01 0.339E+01 -.652E+01 -.601E+00 -.347E+00 -.659E-02 -.942E-05 0.128E-04 0.168E-04
-.226E+02 0.153E+02 0.759E+01 0.252E+02 -.168E+02 -.759E+01 -.254E+01 0.147E+01 -.330E-02 0.191E-04 -.841E-04 -.472E-04
-.403E+01 -.817E-01 0.134E+02 0.476E+01 0.484E+00 -.134E+02 -.789E+00 -.443E+00 0.170E-01 0.141E-03 -.605E-04 -.421E-03
0.557E+01 -.552E+01 0.952E+01 -.618E+01 0.588E+01 -.952E+01 0.605E+00 -.355E+00 -.295E-02 -.467E-04 0.113E-03 -.163E-03
-.787E+00 0.618E+01 0.702E+01 0.791E+00 -.689E+01 -.701E+01 -.145E-02 0.695E+00 -.713E-02 0.557E-05 -.246E-04 -.127E-04
0.789E+00 -.941E+00 0.705E+01 -.150E+01 0.135E+01 -.704E+01 0.774E+00 -.447E+00 -.821E-02 0.147E-04 0.244E-05 -.129E-04
-.167E+01 0.824E+00 0.783E+01 0.168E+01 -.165E+01 -.783E+01 -.257E-02 0.894E+00 -.121E-02 0.511E-04 0.411E-04 -.489E-04
0.229E+02 0.127E+02 0.644E+01 -.255E+02 -.142E+02 -.643E+01 0.254E+01 0.146E+01 -.561E-02 -.918E-05 -.628E-05 0.892E-05
0.413E+01 0.378E+01 0.195E+02 -.413E+01 -.378E+01 -.195E+02 0.217E-02 -.198E-02 0.402E-02 -.175E-03 -.160E-03 -.229E-03
-.557E+00 -.325E+00 -.948E+02 0.555E+00 0.325E+00 0.999E+02 -.173E-02 0.154E-02 -.505E+01 0.571E-05 -.651E-06 -.125E-04
-.104E+01 -.562E+00 -.671E+02 0.105E+01 0.558E+00 0.621E+02 -.423E-02 0.122E-02 0.505E+01 0.690E-05 -.803E-07 0.240E-04
-----------------------------------------------------------------------------------------------
0.620E-02 -.501E-03 0.442E-01 -.708E-13 -.449E-13 -.213E-13 -.639E-02 0.687E-03 -.423E-01 -.753E-04 -.485E-04 -.187E-02
POSITION TOTAL-FORCE (eV/Angst)
-----------------------------------------------------------------------------------
6.37425 2.28557 7.50000 -0.001605 0.003845 0.002764
5.16649 4.37748 7.50000 0.003170 -0.005716 0.002449
2.64138 0.00387 7.50000 -0.002386 -0.007224 0.000779
1.32404 2.28557 7.50000 -0.010388 0.006816 -0.024905
-0.00000 4.44461 7.50000 0.001935 -0.000932 0.002003
5.05691 0.00387 7.50000 -0.001562 -0.004567 0.001067
3.84915 2.22230 7.50000 0.008222 0.007166 -0.001796
2.53180 4.37748 7.50000 -0.007159 -0.000781 0.005802
0.00000 1.81776 7.50000 0.004373 -0.003221 0.004509
-1.27171 3.71038 7.50000 -0.001289 -0.000220 0.000382
-2.27492 5.75803 7.50000 -0.000918 0.008563 0.002159
2.58325 1.49144 7.50000 -0.003945 -0.004718 -0.006414
1.27171 3.71038 7.50000 -0.000112 0.002363 0.001993
0.00000 5.91306 7.50000 0.001447 -0.000846 0.003556
5.11504 1.49144 7.50000 0.001009 0.001803 0.001586
3.84914 3.68404 7.50000 0.002813 -0.002675 0.003278
2.27492 5.75803 7.50000 -0.001662 0.000588 -0.000396
0.00000 0.00000 7.50000 0.009675 0.005593 0.011736
1.92457 1.85192 10.93502 -0.005691 0.000163 0.011510
1.92457 1.85192 10.18466 0.004073 -0.005999 -0.022063
-----------------------------------------------------------------------------------
total drift: -0.000272 0.000138 0.000023
Again, I think that the forces are far from being converged.
I shall say that I am running a calculation with the Gimme method for vdW interactions (LVDW=True, VASP5.4.1), as I am trying to calculate adsorption various species on graphene.
Any suggestions/comments will be highly appreciated.
David
Thanks for your reply.
Firstly, I don't think the forces should matter since I am using the energy criterion for convergence (EDIFFG = 0.1E-03).
However, checking the forces after the last ionic step (after which VASP ends saying that the convergence was reached) is:
FORCES acting on ions
electron-ion (+dipol) ewald-force non-local-force convergence-correction
-----------------------------------------------------------------------------------------------
0.327E+02 0.579E+01 0.698E+01 -.355E+02 -.530E+01 -.697E+01 0.279E+01 -.494E+00 -.659E-02 -.133E-04 0.127E-04 -.141E-04
0.207E+02 0.245E+02 0.643E+01 -.216E+02 -.271E+02 -.642E+01 0.967E+00 0.267E+01 -.677E-02 0.198E-04 0.355E-05 0.158E-04
-.116E+02 -.275E+02 0.948E+01 0.135E+02 0.297E+02 -.948E+01 -.183E+01 -.216E+01 -.161E-02 0.671E-04 -.917E-04 -.156E-03
-.298E+02 0.473E+01 0.134E+02 0.325E+02 -.423E+01 -.135E+02 -.278E+01 -.500E+00 0.450E-02 -.927E-04 0.923E-04 -.421E-03
0.803E+00 -.930E+00 0.703E+01 -.804E+00 0.930E+00 -.702E+01 0.301E-02 -.638E-03 -.821E-02 -.117E-04 0.210E-04 -.135E-04
0.977E+01 -.299E+02 0.657E+01 -.116E+02 0.321E+02 -.656E+01 0.182E+01 -.217E+01 -.625E-02 -.219E-05 -.704E-05 0.141E-04
-.299E+01 -.584E+00 0.955E+01 0.301E+01 0.593E+00 -.955E+01 -.101E-01 -.617E-03 -.551E-02 0.916E-04 -.960E-05 -.156E-03
-.215E+02 0.220E+02 0.795E+01 0.225E+02 -.247E+02 -.795E+01 -.970E+00 0.266E+01 -.761E-03 -.381E-05 0.611E-04 -.610E-04
0.308E+01 -.263E+02 0.965E+01 -.309E+01 0.292E+02 -.966E+01 0.118E-01 -.293E+01 -.197E-03 -.134E-03 0.363E-04 -.182E-03
-.386E+01 -.304E+01 0.653E+01 0.447E+01 0.339E+01 -.652E+01 -.601E+00 -.347E+00 -.659E-02 -.942E-05 0.128E-04 0.168E-04
-.226E+02 0.153E+02 0.759E+01 0.252E+02 -.168E+02 -.759E+01 -.254E+01 0.147E+01 -.330E-02 0.191E-04 -.841E-04 -.472E-04
-.403E+01 -.817E-01 0.134E+02 0.476E+01 0.484E+00 -.134E+02 -.789E+00 -.443E+00 0.170E-01 0.141E-03 -.605E-04 -.421E-03
0.557E+01 -.552E+01 0.952E+01 -.618E+01 0.588E+01 -.952E+01 0.605E+00 -.355E+00 -.295E-02 -.467E-04 0.113E-03 -.163E-03
-.787E+00 0.618E+01 0.702E+01 0.791E+00 -.689E+01 -.701E+01 -.145E-02 0.695E+00 -.713E-02 0.557E-05 -.246E-04 -.127E-04
0.789E+00 -.941E+00 0.705E+01 -.150E+01 0.135E+01 -.704E+01 0.774E+00 -.447E+00 -.821E-02 0.147E-04 0.244E-05 -.129E-04
-.167E+01 0.824E+00 0.783E+01 0.168E+01 -.165E+01 -.783E+01 -.257E-02 0.894E+00 -.121E-02 0.511E-04 0.411E-04 -.489E-04
0.229E+02 0.127E+02 0.644E+01 -.255E+02 -.142E+02 -.643E+01 0.254E+01 0.146E+01 -.561E-02 -.918E-05 -.628E-05 0.892E-05
0.413E+01 0.378E+01 0.195E+02 -.413E+01 -.378E+01 -.195E+02 0.217E-02 -.198E-02 0.402E-02 -.175E-03 -.160E-03 -.229E-03
-.557E+00 -.325E+00 -.948E+02 0.555E+00 0.325E+00 0.999E+02 -.173E-02 0.154E-02 -.505E+01 0.571E-05 -.651E-06 -.125E-04
-.104E+01 -.562E+00 -.671E+02 0.105E+01 0.558E+00 0.621E+02 -.423E-02 0.122E-02 0.505E+01 0.690E-05 -.803E-07 0.240E-04
-----------------------------------------------------------------------------------------------
0.620E-02 -.501E-03 0.442E-01 -.708E-13 -.449E-13 -.213E-13 -.639E-02 0.687E-03 -.423E-01 -.753E-04 -.485E-04 -.187E-02
POSITION TOTAL-FORCE (eV/Angst)
-----------------------------------------------------------------------------------
6.37425 2.28557 7.50000 -0.001605 0.003845 0.002764
5.16649 4.37748 7.50000 0.003170 -0.005716 0.002449
2.64138 0.00387 7.50000 -0.002386 -0.007224 0.000779
1.32404 2.28557 7.50000 -0.010388 0.006816 -0.024905
-0.00000 4.44461 7.50000 0.001935 -0.000932 0.002003
5.05691 0.00387 7.50000 -0.001562 -0.004567 0.001067
3.84915 2.22230 7.50000 0.008222 0.007166 -0.001796
2.53180 4.37748 7.50000 -0.007159 -0.000781 0.005802
0.00000 1.81776 7.50000 0.004373 -0.003221 0.004509
-1.27171 3.71038 7.50000 -0.001289 -0.000220 0.000382
-2.27492 5.75803 7.50000 -0.000918 0.008563 0.002159
2.58325 1.49144 7.50000 -0.003945 -0.004718 -0.006414
1.27171 3.71038 7.50000 -0.000112 0.002363 0.001993
0.00000 5.91306 7.50000 0.001447 -0.000846 0.003556
5.11504 1.49144 7.50000 0.001009 0.001803 0.001586
3.84914 3.68404 7.50000 0.002813 -0.002675 0.003278
2.27492 5.75803 7.50000 -0.001662 0.000588 -0.000396
0.00000 0.00000 7.50000 0.009675 0.005593 0.011736
1.92457 1.85192 10.93502 -0.005691 0.000163 0.011510
1.92457 1.85192 10.18466 0.004073 -0.005999 -0.022063
-----------------------------------------------------------------------------------
total drift: -0.000272 0.000138 0.000023
Again, I think that the forces are far from being converged.
I shall say that I am running a calculation with the Gimme method for vdW interactions (LVDW=True, VASP5.4.1), as I am trying to calculate adsorption various species on graphene.
Any suggestions/comments will be highly appreciated.
David
-
alex
- Hero Member
- Posts: 585
- Joined: Tue Nov 16, 2004 2:21 pm
- License Nr.: 5-67
- Location: Germany
Re: Stopping ionic relaxation
Hi David,
you are definitively right about convergence, but your last line tells :'total drift: -0.000272 0.000138 0.000023'. So you are close to your criterion.
I'd suggest you decrease EDIFFG further and set it to a negative value as outlined in the manual:
http://cms.mpi.univie.ac.at/wiki/index.php/EDIFFG
For weak interactions you'll have only tiny changes in energy (however, not in your case).
Cheers,
alex
you are definitively right about convergence, but your last line tells :'total drift: -0.000272 0.000138 0.000023'. So you are close to your criterion.
I'd suggest you decrease EDIFFG further and set it to a negative value as outlined in the manual:
http://cms.mpi.univie.ac.at/wiki/index.php/EDIFFG
For weak interactions you'll have only tiny changes in energy (however, not in your case).
Cheers,
alex