Search found 46 matches

by cenwanglai
Sun Dec 14, 2014 6:34 am
Forum: VTSTTools
Topic: CNEB with vdW corrections
Replies: 0
Views: 18164

CNEB with vdW corrections

code: vasp5.2, PBE+D2 calculation, CNEB >nebef.pl 0 0.00000000 -670.54295300 0.00000000 1 0.03416700 -670.54117300 0.00178000 ! It shows the image 1 is at an extrema. 2 0.03161900 -670.54493200 -0.00197900 3 0.04730700 -670.56123200 -0.01827900 4 0.02543000 -670.58572300 -0.04277000 But, in the 02/O...
by cenwanglai
Sat Nov 12, 2011 1:51 am
Forum: VTSTTools
Topic: optimizer, EDIFF, and DdR in dimer
Replies: 0
Views: 12328

optimizer, EDIFF, and DdR in dimer

(1) In the dimer example provided in the website, CG (OPTIM = 2) was used. Could I change to LBFGS or other NEB optimizer? In my dimer run when CG optimizer employed, it did not seem to be aggressive because only 0.001 ev or even lower energy decreases for steps. (2) It seems that the EDIFF affects ...
by cenwanglai
Thu Oct 13, 2011 3:03 am
Forum: VTSTTools
Topic: What is the tage DNdR for? It is DdR instead?
Replies: 2
Views: 6997

Re: What is the tage DNdR for? It is DdR instead?

When I set the DdR to 0.01, the Torque decreases to a much small value around 1 drastically, with a minus curvature.

Everything seems to be going well.
by cenwanglai
Wed Oct 12, 2011 11:55 pm
Forum: VTSTTools
Topic: What is the tage DNdR for? It is DdR instead?
Replies: 2
Views: 6997

What is the tage DNdR for? It is DdR instead?

In the page http://theory.cm.utexas.edu/vtsttools/dimer/ It suggests to incease the finite difference distance DNdR to 0.01 to make the Torque drop systematically as the dimer rotates. I can not find any DNdR in the OUTCAR file. Does it mean DdR (the dimer separation)? In my dimer run, the Angle can...
by cenwanglai
Wed Oct 12, 2011 1:42 pm
Forum: VTSTTools
Topic: How can I restart a dimer rum?
Replies: 0
Views: 10462

How can I restart a dimer rum?

>cp CONTCAR POSCAR >cp NEWMODECAR MODECAR ? My dimer run had been converged to 0.03 eV/Angstrom and there were three imaginary frequencyies f/i: 80 cm-1, 118 cm-1 and 256 cm-1. The displacements for 256 cm-1 is in the direction of NEB reaction chain to form product configuration. Main tags for frequ...
by cenwanglai
Tue Oct 11, 2011 1:36 am
Forum: VTSTTools
Topic: Is my dimer run reasonable?
Replies: 2
Views: 6903

Re: Is my dimer run reasonable?

Thanks. This is my first dimer run.
by cenwanglai
Sun Oct 09, 2011 5:18 pm
Forum: VTSTTools
Topic: Is my dimer run reasonable?
Replies: 2
Views: 6903

Is my dimer run reasonable?

This is my dimer calucaltion after having been converged to 0.02.

Does it seem to be converging?

Some tags of My INCAR:

EDIFF = 1E-7
EDIFFG = -0.001
IBRION = 3
POTIM = 0
NSW = 300

IOPT = 2
DRotMax = 5
DdR = 1E-2

PW91 + U is considered with a single Gamma point for my 83 atoms supercell.
by cenwanglai
Fri Oct 07, 2011 11:11 pm
Forum: VTSTTools
Topic: Total energy of the saddle image sensitive to K sampling
Replies: 1
Views: 6192

Total energy of the saddle image sensitive to K sampling

I have converge my CNEB to 0.05 with a single Gamma K-point. When I switched the saddle image to SCF total energy calculation with more K points (3 * 3 * 1), the latter is higher at ~ 0.1 eV in energy. And, the total force of scf calulation is seem to be unconverged (for some free atom, the force is...
by cenwanglai
Fri Oct 07, 2011 9:13 am
Forum: VTSTTools
Topic: Dimer from NEB...moving away from saddle point?
Replies: 5
Views: 10934

Re: Dimer from NEB...moving away from saddle point?

What does the DFT + U matter to the dimer calculation?

Is there any problem comparing to DFT without U correction?
by cenwanglai
Fri Sep 23, 2011 11:50 am
Forum: VTSTTools
Topic: a continuum solvation model in vasp?
Replies: 4
Views: 17728

Re: a continuum solvation model in vasp?

Prof. Liu = Liu Zhipan?
by cenwanglai
Wed Sep 21, 2011 2:56 pm
Forum: VTSTTools
Topic: Extrema images in CL-NEB and distances between images
Replies: 3
Views: 11107

Re: Extrema images in CL-NEB and distances between images

Graeme, the line (NEB: no climbing image found) disappeared when I set the EFIRST to a value between the energy 01 image and 04.

I think I have got your points in EFIRST and ELAST in INCAR.

Cheers ~
by cenwanglai
Tue Sep 20, 2011 1:32 pm
Forum: VTSTTools
Topic: Extrema images in CL-NEB and distances between images
Replies: 3
Views: 11107

Re: Extrema images in CL-NEB and distances between images

Dear Graeme, you are so helpful! I love you! ~ I put a small molecule in the slab vacuum 4 Angstrom from the surface. The molecule will be adsorbed to the surface and react with pre-adsorbed surface species. In this process, there is a energy barrier. So the initial geometry is true acting as a gues...
by cenwanglai
Mon Sep 19, 2011 11:47 pm
Forum: VTSTTools
Topic: Extrema images in CL-NEB and distances between images
Replies: 3
Views: 11107

Extrema images in CL-NEB and distances between images

[attachment=0]CNEB.png[/attachment] I am running a Cl-NEB run and now the nebef.pl results read like above. We can find two extrema in energy: the local minimum of image 2 at -0.0675 and the maximum of image 4 at -0.0299 ref to initial image 00. When I check the OUTCAR of all the images, I am puzzle...
by cenwanglai
Tue Aug 23, 2011 3:32 am
Forum: VTSTTools
Topic: optimizer for CNEB
Replies: 1
Views: 6351

optimizer for CNEB

“We recommend using CG or LBFGS when accurate forces are available. This is essential for evaluating curvatures. For high forces (far from the minimum) or inaccurate forces (close to the minimum) the quick-min or FIRE methods are recommended. These two methods do not rely on curvatures, and tend to ...
by cenwanglai
Mon Aug 22, 2011 8:42 am
Forum: VTSTTools
Topic: How to make a ZPE correction for saddle point?
Replies: 1
Views: 8636

How to make a ZPE correction for saddle point?

For a freqence-aimed run by IBRION = 5 with several involved atoms movable, we can get real several frequences and an intensive imaginary freqence. Each of the frequences (fi): ZPEi=0.5hfi ZPE(total)=sum of all the ZPEi E(corrected)= E+ZPE(total) Is it right? And how to treat about the imaginary fre...