UT theoretical chemistry code forum

This is a good question, but one that I feel is a little difficult to answer. The reason that it is difficult is that it depends upon what information you want to extract from the frequencies. It is also a little complicated because it can depend upon if you have frozen atoms in the system. In the c...

If you are doing an NEB calculation, each image should read the wavecar (if present) in its own directory.

Hi Abid, Yes, for sure, this is critical, and I think we have very limited documentation about visualization. First, there are a few scripts in the eon/tools directory which might help visualize the processes available from a particularly state, eon-prmov.sh, but the primary tool for making movies i...

I think that you want the all-electron (valence+core) but based upon the total charge in your calculation (248 e) it seems that you only have the valence density in your analysis.

It looks to me like you don't have core charges included. Your N atoms has a charge over 8, which is including the charge on the 3 H atoms. You can still estimate the charge transfer from the Boron surface to the NH3 molecule as 8.1-8=0.1e, but you really need core charges to resolve the charge dens...

That is really a question about the science If you are trying to get an activation energy for a vacancy migration in a bulk material, I would recommend keeping both the cell size and shape fixed.

The script is working as it should. The issue is that you are moving almost exactly 1/2 way across the box in the y-direction between images 0 and 2. In our script, we find the shortest path between the initial and final states relative to the periodic boundary conditions. For the first atom, it is ...

It looks like you have 90 atoms in your DISPLACECAR and only 87 in your POSCAR.

You can install ASE locally - it does not have to be installed system-wide. In regards to changing neb.F, stress is a 3x3 matrix. In our code it is an upper-diagonal matrix, which is why the following elements: stress(2,1)=0._q stress(3,1)=0._q stress(3,2)=0._q are set to zero. In your case, you can...

Hi Zhifenh, One option is to use the SSNEB through tsase. ASE provides the ability to apply such general constraints. You could also modify neb.F in a similar way to how you modified constr_cell_relax.F. For example, around line 236 you could zero all the elements of the stress except for the 3,3 te...

That is very likely correct.

Well, you would need to extract the forces and take a dot product with the tangent between images. I don't think that we have a script for doing this, but it wouldn't be too hard.

My guess is that you do not have our VTSTcode linked into your vasp binary. You can grep for VTST in the OUTCAR to check.

You can download the scripts here: https://theory.cm.utexas.edu/vtsttools/download.html

It should be compatible with vasp 6 - I don't know of any changes to the format of the XDATCAR.

Hi Qian, I'm not really sure what cp2k does when it evaluates an empirical potential, but I could imagine that there is a significant overhead in running cp2k to evaluate a simple Morse interaction. To check this, you might just check the time to calculate a single point energy and force with cp2k a...