UT theoretical chemistry code forum

In the attached, I've used some cheaper computational settings, which I recommend for saddle point calculations. I also froze one atom to get rid of zero modes. Then, a conservative optimizer with a sufficient number of images appears to result in a NEB calculation that is systematically converging.

I used less computationally expensive settings and somewhat more conservative optimizer settings to reconverge both the endpoints and the neb. The primary barrier is 0.82 eV, but note that it looks like it will be a two-step process. The high spring constant for the CO2 molecule required a lower tim...

That is exactly right - but make sure to set NSW to 25. It may still work with a larger value, but I'm not sure.

When you calculate the zero point energy, remember to remove the 6 near-zero modes, corresponding to translation and rotation.

Yes, that bader code should work for that.

The submit script can remain the same for an NEB calculation; you just need to add the IMAGES tag to your INCAR file.

Yes, that works just fine. You can relax a structure, and the charge density files will be printed at the end of the calculation.

Yes, that is right. The built in NEB calculator in vasp is fine, but it does not have the climbing image or NEB-aware optimizers.

Most likely, you do not have our vtstcode linked into your vasp binary. You can grep for "VTST" in your OUTCAR to check.

Yes, it is available for commercial use. Anyone can use if for any purpose.

I can't; I don't know what is going wrong. This is a problem internal to the vasp code and it needs to be sorted out by the vasp developers.

Yes, I have seen problems with AECCAR0 files but I don't know why it happens. This is a question for the vasp guys.

Well, I see what you mean. I can reproduce the problem but I'm not sure what's going on.

I'll keep poking at it.

I would have to see more about the calculation to try to understand why the energy is dropping slowly. For example, are there soft modes in the system such as rotations or translations along which the energy changes slowly? Also, seeing the INCAR and OUTCAR would help. If you want to make a tar.gz o...

It sounds like you know both the initial and final states of your reaction of interest. I suggest using an NEB calculation to find the saddle point that connects them.

It's true that the total spin will be an integer, but the integrated spin around an atom does not need to be.

This is similar to the charge of an atom. We typically think about formal (integer) charges, but in reality electrons do not completely localize on atoms in the solid state.