UT theoretical chemistry code forum

I think it's fine to do a few steps using a small time step, but I recommend turning on the climbing image right afterwards. I don't think it makes sense to converge the neb without climbing image and then turn it on. Also, if you are willing to try a new method, we would be very interested to see i...

Non-orthogonal cells should be properly treated in the version of the code which is in cvs. cvs -d :pserver:anonymous@theory.cm.utexas.edu:/Groups/cvs login cvs checkout bader use the password 'anonymous' when prompted. We're in the process of making significant changes to the code, but the original...

The variable VTST_ZIP can be set to gzip (the default) or bzip2. The later tends to have a higher compression ratio.

1) I can't see a situation that would result in a saddle point with an energy less than the initial minimum. By definition, the initial state should be reached by minimizing from the saddle point. That said, within the general transition state theory, you can choose a valid transition state (an N-1 ...

It's actually the highest energy image which is moved up in energy to the saddle point. This would typically be the image which is closest to the extrema of highest energy, but the two definitions are not the same. (I think they are the same only for a harmonic potential at the saddle). I have never...

The climbing image is only used for the highest energy image along the path. In principle, the algorithm could be applied to any local maximum (and/or minimum) along the path, but we have done this with the implementation in vasp. Usually when an intermediate minimum is found, it's easier to minimiz...

It may have to do with the fact that you have to log in to post a message. We do not allow anonymous messages. You should, however, be able to log in once, and check that you get logged in automatically from your computer.

Your results look just fine to me. The H atom is next to Mg atoms, so it makes sense for the H to accept an extra electron from the Mg. You can certainly try to correlate charge transfer with binding energy. It's not clear to me if the asymmetric charges are a problem. Your without H is a much small...

Yes, that should be fine. If you post the configuration (POSCAR file) or send us a .tar.gz file of the run, we could take a closer look to make sure things are working properly.

Yes, although it seems a little strange. Is the H atom is in a very electro-rich environment? Also, there are several versions of the H pseudopotential which have different charges, for terminating bonds. Make sure you have the standard 1 electron pseudopotential.

Try using the Mg_sv or Mg_pv pseudopotentials. With only 2 valance electrons using the default pseudopotential, the maximum at the Mg core is not present.

Avoid using the Voronoi charges. They are a very rough measure of the charge around each atom, but they should not be taken seriouly.

I'll get this out within two weeks. We are making other changes as well which will not be finished, but I'll get a beta version in cvs with proper support for non-orthogonal vectors. It's motivating to know that someone is actually waiting for it to be done. In many cases you can make an orthogonal ...

Andri, have you seen a smaller ediff value (going from a normal value of 1e-5 to to a smaller value of 1e-8) effect the bader charges?

Yes, one way to improve the precision is to use a finer charge density grid. You can do this by specifying NGXF, NGYF and NGZF in the INCAR file. I usually look in the OUTCAR or CHGCAR file to see what it is by default, and then multiply the default values by 1.5 or 2.

The number of images needed is dependent upon the length and curvature of the path. For C diffusion in bulk Ni, the path should be fairly straight, if you diffusion path goes between neighboring sites. I would definitely recommend starting with less expensive parameters. If you use the soft C_s paw ...