UT theoretical chemistry code forum

Just to make sure that it's clear, EDIFF is the electronic convergence and controls the accuracy of the forces. 1) You can get a well converged structure using a more standard value for EDIFF of 1e-4 or 1e-5. 2) For a dynamical matrix calculation, you should have accurate forces because you are doin...

These are some very good suggestions. The reason our group is using the Bader analysis is primarily to decompose charges, density of states, and energy into local contributions per atom. We do not have any expertise in the AIM theory and this is the only reason that we have not calculated some of th...

You can specify RWIGS in vasp to do this.

I hope that ISYM is the problem. I just ran the calculation and got the following modes: 1112.247957 cm^{-1} ... 1 393.774277 cm^{-1} ... 1 122.754647 cm^{-1} ... 1 73.095249 cm^{-1} ... 1 62.813129 cm^{-1} ... 1 179.409466 cm^{-1} ... 0 346.386662 cm^{-1} ... 0 496.782180 cm^{-1} ... 0 973.566811 c...

Another idea: try ISYM=0 in the INCAR

I should have been a little more explicit: when you change sigma, use different orders of magnitude such as 0.1, 0.01, 0.001. See if there is any occupancy in the excited state.

I'll also give this a try and see what I get.

Something is still wrong. Try two different tests (a) increase the displacement to 0.005 (b) reduce ediff to 1e-8, using the original displacement of 0.001 If you get more reasonable modes with the more accurate forces (test b) then also try using a gaussian or fermi smearing with a low value of sig...

Try setting ediffg to a very small value, such as ediffg=-1e-8. This will force vasp to run all 19 iterations. My guess is that it only ran one, decided that it was converged, and then quit.

We'll work on a fix for this bug in our code.

What ever number of images you choose, you should converge the band so that the forces are low (<0.1 eV/Ang). It doesn't make any sense to draw conclusions from un-converged images. If you have a complex pathway, a single image may not converge. By this, I mean that the force stays high and the imag...

Yes, that is exactly right. Just make sure to remove the 6 lowest modes (rotation and translation) from the modes.dat file before calculating the zero point energy.

Well, and set NSW correctly; don't make it larger than it should be. It might still work, but the program might also hang.

We have recently been fiddling with this script. Our attempt at defining an automatic integration window seemed like a good idea, but we have basically decided that it is not robust enough to use as the default. Integrating over the entire energy range in the DOS is at least robust, but as you are s...

yes

The distance is cumulative along the path. If you started with a linear path and now have a converged curved path, the distance between the initial and final states will be longer.

Yes, where the distance is the sum of the collective motion of all of the atoms.

Sure, you can copy the CONTCAR files to the POSCAR files and continue. We also have a little script for doing this, which works for regular, neb, and dimer calculations called vfin.pl. If you are in your main run directory and you execute 'vfin.pl run1', all of the previous calculation information w...