UT theoretical chemistry code forum

Hi，everyone. The endpoint images are fully minimized using EDIFF=1.E-04 and EDIFFG=-0.02. But the Vasp TSTtools say “……these modifications to the force mean that the energy is no longer consistent with the force being optimized”. How can I set the two parameters for cNEB calculation？Many thanks.

Dear graeme,
I am sure that the endpoint images are fully minimized. But there really is a local minimum in the spline interpolation. So I try minimizing images 01 and 04. Moreover I also use the posinterp.pl script to find an image near the interpolated minimum. But the CONTCAR will change a lot ...

I have performed a investigation of the penetration of CH4 through a monolayer using cNEB method. I choose 4 images，and the initial and final states are above and below the layer，respectively. As a result，we can see from the mep.eps that their are some energies lower than ones of initial or final ...

"Vasp TST tools" say that “……we present a set of optimizers that are all force-based so they can be used with the NEB and min-mode following methods. To use them, the INCAR must set IBRION=3 and POTIM=0, to disable the built in optimizers.” Therefore, I set IBRION=3 and POTIM=0. But the error in ...

The more images I use, the more time it will cost. Right？Generally speaking, how many images may I use in order to get the saddle point using cNEB. Many thanks！

The usual stdout of the image 02, 03,……, number of images is redirected to the files 02/stdout, 03/stdout etc. (Only image 01 writes to the usual stdout). What is the meaning in details? Thank you very much.
Another question: I set EDIFFG=-0.03 in the INCAR, the forces of OUTCAR in image 01 has <0 ...

By the way, the contents of exts.dat file are as follows：
Extrema 1 found at image 0 with energy: 0
Extrema 2 found at image 0.9664 with energy: 0.03588
Extrema 3 found at image 1.00345 with energy: 0.03573
Extrema 4 found at image 4.97809 with energy: 1.59047
Extrema 5 found at image 6.02624 with ...

The contents of the neb.dat file are as follows：
0 0.00000 0.00000 0.00000 0
1 0.57878 0.03575 0.01385 1
2 1.15495 0.9684 -2.87329 2
3 1.72417 1.54421 -0.09036 3
4 2.29537 1.57097 -0.03536 4
5 2.86048 1.59045 0.00321 5
6 3.54456 1.56574 0.03835 6
7 4.23201 1.31292 1.80079 7
8 4.91565 0.03651 0.02382 ...

part of the spline.dat are as follows：
5 1.59045
5.05 1.59024
5.1 1.58982
5.15 1.58921
…… ……
6.4 1.59179
6.45 1.59252
6.5 1.59078
…… ……
so, 1.59045 is not the maximum. And image 5 is not the saddle point. Why? Thank you very much!

The results of nebef.pl are as follows:
0 0.00000000 -168.19069600 0.00000000
1 0.01305000 -168.15477200 0.03592400
2 0.02422600 -167.25659400 0.93410200
3 0.01487900 -166.64542600 1.54527000
4 0.00908800 -166.62037000 1.57032600
5 0.00092800 -166.60048900 1.59020700
6 0.00477000 -166 ...

I have finished a cNEB calculation. But the mep.eps shows that there is no image sits right at the saddle point.Why？Please give me some suggestion, thank you very much!the INCAR is as follows：
PREC = Accurate
ISTART = 0
ICHARG = 2
ENCUT = 400
IMAGES = 8
SPRING = -5
ICHAIN = 0
LCLIMB = T
IOPT ...