NEB result strange

victory2401 · Post by **victory2401** » Thu Jan 08, 2009 3:32 am

Dear Admin!
I am running the CL-NEB for the dehydrogenation from CH3CHOH to CH3COH on Pt(111) using the nebmake.pl to creat the images with the INCAR like this:

INCAR
ISTART = 0
ICHARG = 2

general:
ENMAX = 400
ISMEAR = 1
SIGMA = 0.2
VOSKOWN = 1
SPRING = -5
IMAGES = 3
LCLIMB = .TRUE.

dynamic:
NSW=500
POTIM = 0.2
IBRION = 1

K-Points
0
Monkhorst-Pack
5 5 1
0 0 0

But after convergence, I used the nebbarrier.pl to analysis the result, it is so strange like this:

NEB.dat:
0 0.000000 0.000000 -0.062105 0
1 1.305198 -0.037950 0.000000 1
2 2.776747 -0.071765 0.000000 2
3 4.083341 -0.177778 0.000000 3
4 5.385569 -0.177999 -0.024760 4

exts.dat
Extrema 1 found at image 0.172145 with energy: 0.006577
Extrema 2 found at image 1.000000 with energy: -0.037950
Extrema 3 found at image 2.000000 with energy: -0.071765
Extrema 4 found at image 3.000000 with energy: -0.177778
Extrema 5 found at image 3.671174 with energy: -0.182719

nebef.dat
0 0.00000000 -111.12928800 0.00000000
1 0.00000000 -111.16723800 -0.03795000
2 0.00000000 -111.20105300 -0.07176500
3 0.00000000 -111.30706600 -0.17777800
4 0.00000000 -111.30728700 -0.17799900

So the energy of the TS is even lower than the IS, so what is the problems here?
Thank you very much.