UT theoretical chemistry code forum

graeme wrote:
> You can certainly add more images by interpolation. It is best if you can
> try to keep equal spacing, so for example, going from a 4 image to a 9
> image calculation. You can always keep the climbing image on.

My purpose is to get the proper structures from the high-resolute images ...

Increasing images requires more computer resources.
If we have multiple TS between locally stable images, we may split the one whole NEB run into separate NEB runs.
However, how can I increase the resolution if I need more images, i.e., the high resolution?

Can I run NEBs as if the following?

1 ...

Then, I'll need to check ASE.

Thank you, professor.

Hi, VTSTTools

I'm trying to create images from trans to cis transition.
But some of the structures created in the image seem to cause a warning message.

| The distance between some ions is very small |
| please check the nearest neighbor list in the OUTCAR file |
| I HOPE YOU KNOW, WHAT YOU ARE ...

Thank you, professor.

These are your comments. And I added queries for each comment.

- Make sure that you relax with a force criterion (EDIFFG < 0)
-- The relaxed endpoints are quite different in the attached path because of this

I searched the meaning of this Tag, and it means "If EDIFFG is negative it has a different ...

I've prepared four calculations.
0_NEB is the 1st one, and 3_NEB is the last one.

Below is the description of what I did.

0_NEB: the first initial and final trial POSCAR, POTIM=0.01
not convergent for the calculation
images seem to be divergent. (See each CONTCAR in the image folder)

1_NEB: the ...

Preparing the example for you.
By the way, I wonder the difference between inserting OUTCARs into 00 and 04 (if IMAGES = 4) folders and not.

I'm still suffering from the divergence.
I guessed the reason is that the two C2H4 want to be separated from one another until all C2H4 has the same distance, considering the adjacent cells.

And, then I expand the cell size to lower the interaction between nearest cells, but it takes too long time ...

You said 'forces,' but what did you mean by 'forces'?
+ How can I check that and before or after the NEB calculation?
And 'small time step' means the TIME-tag?

I read a few posts. They mostly said "adjust POTIM and IBRION."
But I want to know how I can decide the value of POTIM and IBRION for all cases?
Does personal experience just govern it?

I tested twice a straightforward example of the chemical reaction

2 C2H4 ---> C4H8

with different INCARs

Here is my first divergent INCAR

SYSTEM = NEB
NCORE = 4
ISTART = 0
ICHARG = 2
ENCUT = 550.0
EDIFF = 0.1E-02
NSW = 250
IBRION = 1
ISIF = 2
ISYM = 1
POTIM = 0.5000
ISMEAR = -5 ...

Gotcha! I've solved the problem. It was my stupid mistake.
The problem was the double chain.o inside .object file.

Thank you so much, graeme! I learn about many things by this by the way.
All I have to do is to enjoy NEB~

Oops! I found out that there are two chain.o in the .object file.
One is for SOURCE, and the another is for SOURCE_GPU.

I wrote extra *.o variable on the SOURCE_GPU. This might cause the error?

And could you let me know the command `make veryclean`? It just removes all files in `build` folder ...

First, `make clean` doesn't work in VASP folder.
(Ok, I'm not good at programming C++, however, I read about make command
that if I want to use 'clean' option, requires predefinition in 'makefile' or 'makefile.include')

Second, what do you mean by removing chain.o before making the VTST version ...