Search found 1848 matches

by graeme
Tue Sep 03, 2019 12:55 pm
Forum: VTSTTools
Topic: Convergence problem of SS-NEB
Replies: 1
Views: 103

Re: Convergence problem of SS-NEB

If you post a .tar.gz file of the calculation (without CHG* WAV* files), I can take a look.
by graeme
Fri Aug 30, 2019 7:18 pm
Forum: VTSTTools
Topic: Please append version numbers to tarballs
Replies: 2
Views: 115

Re: Please append version numbers to tarballs

Yes, for sure. In fact, I currently strip the revision number. Instead, I will change it so that the download contains the version.
Thanks for note.
by graeme
Thu Aug 29, 2019 4:44 pm
Forum: VTSTTools
Topic: Forces are not getting converged
Replies: 1
Views: 126

Re: Forces are not getting converged

This is a strange path. I see that H is moving on the MoTe2 surface. But then there is also a shift between the layers and even a rearrangement of the atoms in the bottom layer. If you are trying to calculate H diffusion on the surface, you need different endpoints. For example, you could take your ...
by graeme
Sat Aug 17, 2019 4:27 am
Forum: Bader
Topic: Zero charge on hydrogen
Replies: 2
Views: 249

Re: Zero charge on hydrogen

Make sure to add core charge by adding the AECCAR0 and AECCAR2. You can then do the Bader partitioning on the total charge and the integration on the valence charge in the CHGCAR. There is more information about this here: http://henkelmanlab.org/code/bader/ in the "Note to Vasp Users" section.
by graeme
Tue Aug 13, 2019 2:48 am
Forum: VTSTTools
Topic: I have a questions when it comes to aKMC script.
Replies: 1
Views: 244

Re: I have a questions when it comes to aKMC script.

This is a very old script which is no longer supported. It has been replaced by the EON code:
http://theory.cm.utexas.edu/eon/
by graeme
Sun Aug 11, 2019 2:22 am
Forum: VTSTTools
Topic: CI-NEB: max force on atom vs TOTAL-FORCE
Replies: 5
Views: 314

Re: CI-NEB: max force on atom vs TOTAL-FORCE

No, that's not going to work. If you have access to sufficient computing resources, you can put the calculation of each image on a separate computer with communication through MPI. Then, when you have a reasonable path, you can switch to the dimer method using the neb2dim.pl script and converge to t...
by graeme
Sun Aug 11, 2019 2:19 am
Forum: VTSTTools
Topic: Using NEB method with gas-phase species
Replies: 0
Views: 361

Re: Using NEB method with gas-phase species

If you know the initial and final states then you can use the NEB go calculate the pathway. Just make sure that the gas phase molecules are separated in the initial and/or final states. Also, since the pathway may be long, in terms of the total atomic motion, make sure to use a sufficient number of ...
by graeme
Thu Aug 08, 2019 2:42 pm
Forum: VTSTTools
Topic: CI-NEB: max force on atom vs TOTAL-FORCE
Replies: 5
Views: 314

Re: CI-NEB: max force on atom vs TOTAL-FORCE

The NEB uses a force projection - only the component of the force on each image perpendicular to the path is used for optimization and the convergence criterion. Yes, the maximum (NEB) force on any atom is what is reported.
by graeme
Wed Aug 07, 2019 12:59 am
Forum: VTSTTools
Topic: Dimer calculation -consistent high torque
Replies: 7
Views: 471

Re: Dimer calculation -consistent high torque

I'm not sure what was going wrong with your original settings. I used the cheap settings, not to solve the problem, but to debug the problem. When I didn't see the high forces with my normal settings, I left it as a solved problem. For some reasons, your original settings appear to give noise in the...
by graeme
Wed Jul 31, 2019 1:53 am
Forum: VTSTTools
Topic: Dimer calculation -consistent high torque
Replies: 7
Views: 471

Re: Dimer calculation -consistent high torque

I did a calculation using what I would consider pretty standard settings for a TS calculation. I cut your slab down a bit, froze the bottom layers, reduced the kpoints, went to soft O and C potentials and lowered the cutoff to 300 eV. In the attached you can see reasonable convergence. I was not goi...
by graeme
Sun Jul 28, 2019 3:30 pm
Forum: VTSTTools
Topic: Dimer calculation -consistent high torque
Replies: 7
Views: 471

Re: Dimer calculation -consistent high torque

Something is not right. I would start by checking to see if the electronic structure is converging to your 1e-7 EDIFF value within your specified 400 NELM steps. If that is not happening, there will be errrors in the force and the torque values will be meaningless. If your forces are converged, then...
by graeme
Sun Jul 14, 2019 6:12 pm
Forum: VTSTTools
Topic: Forces are not minimized even after many steps during CINEB calculation
Replies: 2
Views: 374

Re: Forces are not minimized even after many steps during CINEB calculation

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.
by graeme
Sun Jul 14, 2019 12:53 am
Forum: VTSTTools
Topic: cNEB Diverges in specific images
Replies: 2
Views: 319

Re: cNEB Diverges in specific images

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...
by graeme
Fri Jul 05, 2019 1:57 pm
Forum: VTSTTools
Topic: Can a DynMat calculation for an isolated molecule be done?Can a DynMat calculation for an isolated molecule be done?
Replies: 1
Views: 536

Re: Can a DynMat calculation for an isolated molecule be done?Can a DynMat calculation for an isolated molecule be done?

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.