Hi , I have done a NEB calculation,with INCAR as follow:
General
SYSTEM = 3d metal
PREC = High
ISTART = 0
ICHARG = 0
IMAGES = 8
SPRING = -5
Electronic minimization
ENCUT = 400
ENAUG = 613.6
ISIF = 0
NELM = 80
NELMIN = 4
NELMDL = -12
EDIFF = 1E-4
MAXMIX = 80
LREAL = .FALSE.
Ionic relaxation
ALGO = V
IALGO = 48
NSW = 2000
IBRION = 3
POTIM = 0.1
EDIFFG = -0.05
LCLIMB = .TRUE.
DOS related parameters
ISMEAR = 1
SIGMA = 0.2
Parallel related
LPLANE = .TRUE.
NPAR = 8
LSCALU = .FALSE.
NSIM = 4
and the POSCARs of the two endpoints as follow：
POSCAR1:
system
1.00000000000000
3.9485311115633799 -2.2796855001951202 0.0000000000000000
0.0000000000000000 4.5593710003902297 0.0000000000000000
0.0000000000000000 0.0000000000000000 2.8225838602771001
3
Direct
0.0000000000000000 0.0000000000000000 0.0000000000000000
0.3333333332999970 0.6666666667000030 0.5000000000000000
0.6666666667000030 0.3333333332999970 0.5000000000000000
POSCAR2:
system
1.00000000000000
3.9485311115633799 -2.2796855001951202 0.0000000000000000
0.0000000000000000 4.5593710003902297 0.0000000000000000
0.0000000000000000 0.0000000000000000 2.8225838602771001
3
Direct
0.0000000000000000 0.0000000000000000 0.0000000000000000
0.3333333332999970 0.6666666667000030 0.3333333333300033
0.6666666667000030 0.3333333332999970 0.6666666666699967
and I find the image with highest energy has a CONTCAR like this:
system
1.00000000000000
3.9485311115633799 -2.2796855001951202 0.0000000000000000
0.0000000000000000 4.5593710003902297 0.0000000000000000
0.0000000000000000 0.0000000000000000 2.8225838602771001
3
Direct
0.0000000000000000 0.0000000000000000 0.0000000000000032
0.3333333332999970 0.6666666667000030 0.0556902987026491
0.6666666667000030 0.3333333332999970 0.9443097012973477
0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00
0.00000000E+00 0.00000000E+00 0.00000000E+00
The problem is the atomic positions of this image is out of the scale limited by the two endpoints. Is there any problem? Is this result unreliable?
Thanks for your help all the times！
A question about NEB result
Moderator: moderators
It's not necessarily incorrect - this is a periodic crystal. It is, however, a crystal of 3 atoms in which two are moving a lot. This corresponds to infinite array of translating atoms, or some kind of phase transition. From that point of view, I don't see how the energy barrier could have much meaning, except maybe as the activation energy per unit cell.