UT theoretical chemistry code forum

Let's forget about the solid state optimization for now - it is not important. So I'm not sure that we are on the same page in terms of how the calculation is done. My suggestion is to find a cell geometry that you are happy with and then fix it - just the cell parameters, not the atoms. Now you can...

Well, I have no information about the system and so I can't say much. Typically, if you relax all of the atoms then you should have positive frequencies, however, if you have all atoms free and you have a nice set of positive frequencies and those three near-zero frequencies, they could correspond t...

I would suggest checking both convergence of the structure and the frequencies as a function of sigma. So what I mean by that is to reduce sigma, re-optimize and then recalculate frequencies and check for convergence. But this is not typically a difficult parameter to converge - as long as you see o...

I'm not sure that I entirely understand the question. There is no sense to an NEB calculation when all the atoms are fixed (with a very small caveat that it is possible to do a solid state optimization of the cell with atoms fixed in relative coordinates). You certainly can have fixed atoms in an NE...

First thank you for the note - it is great to have feedback! I think that the instructions for vasp.6.4 are correct. I recently built vasp across quite a few different machines including both for cpu and gpu. Currently, dynamic.F is not being linked in and so does not need to be in the object list. ...

no, just run nebmake.py in the same way that you would nebmake.pl - it will apply the IDPP

Yes, but you may need to set MaxMove to a smallish value to keep the initial steps in the optimization stable.

But better would be to use the nebmake.py script, which will apply the IDPP method and try to keep the bond lengths more constant in your initial band.

You need to reorder the atoms between your initial and final states so that only one atom is moving, rather than half of them.

it looks reasonable

ok, so use those endpoints.

it should work with updates in these two files. (just remove the .txt and put the files in your vtstscripts dir)

Take image 01 and 05 and rerelax them with ISYM=0 to make sure that you have the lowest energy endstates.

Try turning symmetry off for your endpoints. (ISYM=0)

No, the drop in energy between the band images and the endpoints (likely) indicates that you have different settings in the two calculations. If you post the full calculations of both the endpoints and the NEB, I can take a look and see what's going on.

Vesta is correct; I will fix our script and report back when it is done.