Search found 1914 matches

by graeme
Tue Aug 04, 2020 1:29 pm
Forum: VTSTTools
Topic: Confusion about NEB calculation
Replies: 1
Views: 36

Re: Confusion about NEB calculation

Your calculation setting have to be the same for the endpoints and the NEB. In your case, it looks like the endpoints were spin polarized and the NEB was not. If you turn on spin polarization for your band, the energies should line up better.
by graeme
Mon Aug 03, 2020 1:27 pm
Forum: VTSTTools
Topic: CI-NEB forces are fluctuating and calculations cannot converge
Replies: 4
Views: 178

Re: CI-NEB forces are fluctuating and calculations cannot converge

Optimization is a bit of an art. But first, you can use any optimizer that will reach your force criterion. IOPT=3 is a safe and stable optimizer and if you can reach convergence with it (as we did) there is no need to use a different one. That said, IOPT=3 and 7 are first-order optimizers in that t...
by graeme
Sun Aug 02, 2020 10:43 pm
Forum: VTSTTools
Topic: CI-NEB forces are fluctuating and calculations cannot converge
Replies: 4
Views: 178

Re: CI-NEB forces are fluctuating and calculations cannot converge

In the attached calculation, I continued your step2 using the same optimizer (IOPT=3) and it converged fairly rapidly down to 0.1 eV/Ang. I will repeat this with IOPT=1 and find a suitable setting - I expect that you need to reduce INVCURV. The problem with the dimer calculation is that you are usin...
by graeme
Mon Jul 20, 2020 12:27 pm
Forum: VTSTTools
Topic: Problem in interpolation with nebmake.pl script
Replies: 15
Views: 10918

Re: Problem in interpolation with nebmake.pl script

The tangent is a unit vector along the path - it has nothing to do with the force. However, the force on each atom is less than 0.01 eV/Ang: FORCES: max atom, RMS 0.007795 0.003173 and so this image is converged. To check the entire band, you can use the nebef.pl script, which will grep for the forc...
by graeme
Sun Jul 19, 2020 8:24 pm
Forum: VTSTTools
Topic: Problem in interpolation with nebmake.pl script
Replies: 15
Views: 10918

Re: Problem in interpolation with nebmake.pl script

If you look in the OUTCAR, after the lines: POSITION TOTAL-FORCE (eV/Angst) ----------------------------------------------------------------------------------- you can see the NEB forces (total+chain). Then you can also see the forces used for the convergence criterion, as in: FORCES: max atom, RMS ...
by graeme
Sun May 24, 2020 5:45 am
Forum: VTSTTools
Topic: DynamicMatrix_CH4
Replies: 4
Views: 2963

Re: DynamicMatrix_CH4

Wait a sec. I just nicely and rapidly solved the problem that you posted and now you immediately post a different problem?!? No, take a minute to think about your calculation. With the frequencies that I sent, there are 6 zero-ish modes associated with translation and rotation. The others are vibrat...
by graeme
Sat May 23, 2020 5:18 pm
Forum: VTSTTools
Topic: VASP 6.1.0 support
Replies: 3
Views: 1758

Re: VASP 6.1.0 support

Ok, I updated the tar file after writing to you - I realized that I did not update that.
by graeme
Sat May 23, 2020 5:17 pm
Forum: VTSTTools
Topic: DynamicMatrix_CH4
Replies: 4
Views: 2963

Re: DynamicMatrix_CH4

The problem has to do with ISYM. In your calculation, vasp is detecting symmetry so that when you make a small displacement, it is zeroing the components of the force which break symmetry. Additionally, you have a tab instead of a space after your ISYM variable, so that even if you think you are set...
by graeme
Fri May 22, 2020 3:48 pm
Forum: VTSTTools
Topic: VASP 6.1.0 support
Replies: 3
Views: 1758

Re: VASP 6.1.0 support

The most recent version of the VTST code is compatible with vasp.6.1.0. Note that I just recently made this update, so while we have not seen any problems, please let me know if you see any.
by graeme
Sat May 16, 2020 5:02 pm
Forum: Bader
Topic: bader tells different atomic charges of O2
Replies: 1
Views: 9662

Re: bader tells different atomic charges of O2

Try reducing the grid spacing using the NGXF, NGYF, and NGZF. Also try using the -b weight method.
by graeme
Sat Feb 08, 2020 4:21 pm
Forum: Bader
Topic: Atomic boundary trace or contours in a slice of a super-cell
Replies: 19
Views: 10376

Re: Atomic boundary trace or contours in a slice of a super-cell

I've updated the code to v1.04 with a bug fix for printing the Bader volumes.
by graeme
Thu Feb 06, 2020 9:15 pm
Forum: Bader
Topic: Atomic boundary trace or contours in a slice of a super-cell
Replies: 19
Views: 10376

Re: Atomic boundary trace or contours in a slice of a super-cell

I'm just not sure what you are asking for. I explained how to write the charge density in a Bader volume around a single atom. If you want to see a contour plot of the charge density inside that sphere, you can do that with a visualizer (see attached). But I don't really understand the words "draw c...
by graeme
Tue Feb 04, 2020 6:07 pm
Forum: VTSTTools
Topic: double negative imaginary frequency after dimer run
Replies: 2
Views: 4236

Re: double negative imaginary frequency after dimer run

It's not clear to me how the vibrational modes were calculated. The modes in the VASPVIB.MOLF look a little strange in that they contain many zeros - were these calculated on a subset of coordinates? Anyway, frequency calculations at saddles do take some care. I would start by reducing the force in ...
by graeme
Fri Jan 31, 2020 3:56 pm
Forum: VTSTTools
Topic: from converged neb to dimer: ts goes away....
Replies: 2
Views: 2636

Re: from converged neb to dimer: ts goes away....

I've been having trouble with the k221 dimer calculation using the gamma point saddle from the NEB. I'll try to figure out what's going on.

Nice to hear that the k221 NEB worked.
by graeme
Fri Jan 24, 2020 4:51 pm
Forum: Bader
Topic: Atomic boundary trace or contours in a slice of a super-cell
Replies: 19
Views: 10376

Re: Atomic boundary trace or contours in a slice of a super-cell

I get it. I was responding to what I thought was the larger question about how to plot a Bader volume. But yes, I see that we do have a bug in the code and I will try to fix it as soon as I can.