UT theoretical chemistry code forum

Thank you Joshua, I will do it longer. And yes I did change a system a bit to make it a little simpler molecule.

Also, I have tried Dimer method before using NEB image as the starting point, but the forces keep increasing with out decreasing trend at all, so I stopped. Did you have the same issue ...

Hello Prof. Henkelman,

I am dealing with charge analysis of an oxygenated aromatic compound adsorbing on Ni surface, using VASP 5.4.1 with optB88-vdW for dispersion force correction.

In short, the issue I encountered with is that when I included core electrons, the carbon atoms in the ring become ...

Yes please Prof. Attached is the detail of the calculation. Note that initially I used more than one picture for NEB, but the results were initially the same, so I reduced the number of picture to just the one with the highest energy (for quicker calculation) to see in a long run where does it lead ...

Unfortunately, it does not. I have tried suggestions from other posts extensively, including doing damped MD with time step of 0.002, but it still fluctuates heavily with no tendency toward convergence. I have also tried using FIRE method. The results of both of these are attached.

Hi,

I know that in VASP for accurate bader analysis, we need to include core charges and hence we do,

bader CHGCAR -ref CHGCAR_sum

I am wondering if we want to use the weight method is typing

bader -b weight CHGCAR -ref CHGCAR_sum

the correct way to do it or would this result in weight ...

Just an extra information regarding question no. 3 in the previous reply, I did an integration of no. of core electrons from AECCAR0 of a simpler system (just phenol), which is C6H6O1,


therefore principally the core electrons should be 14 electrons



using the maximum accuracy, the core ...

I found a way to "alleviate" the issue. For future new users that may encounter the same issue, you should increase NG(X,Y,Z)F by MANY MANY folds, at least in my case. Increasing this should reduce the negative values in CHGCAR_sum significantly, and hence eradicate oscillation.

In my case, I did ...

I think I know now, it's likely to be because negative values in AECCAR0 correct?, if so do you have any suggestion of what may be the cause, my INCAR is,

SYSTEM = Ni_slab_phenol
PREC = Accurate
ENCUT = 500
IBRION = 2
NSW = 0
ISIF = 2
NELMIN = 6
EDIFF = 1.0e-04
EDIFFG = -0.02
VOSKOWN = 1 ...

Hi Prof.,

I have read through other thread regarding having an error "ERROR: should be no new maxima in edge refinement", I tried checking that the cause of this error is not as you mentioned earlier. My setup is a slab model with spin polarization, van der Waals interaction (optB88-vdW). I have ...

Hello sir,

I attached the file (Dimer.tar.gz) that shows DIMCAR only 1 step. The POSCAR is the initial structure file, and the MODECAR file is generated from modemake.pl of the presumably transition structure from NEB and the initial state.



I think this could have been much easier if I use ...

Hello,

I generated a modecar file using modemake.pl on initial structure and the likely transition state from CNEB. However, when I started it only run once and finished, the energy given is apparently the initial structure energy (POSCAR). In DIMCAR, this is what written

Step Force Torque ...

Thank you Prof. Graeme. Appreciated your quick reply.

Hello all,

I am very new to vtst calculation. I am looking if anyone has encountered similar system as I currently do. The system is a reaction on a surface which is fairly large and also have to take into account van der Waals force. Convergence by CNEB using 5 images took a very long time ...

Hi,

I am doing NEB calculation for a reaction of a rather complicated molecule on a fixed reaction surface. Preliminarily, I am using 3 images with LBFGS method. However, it seems like the molecule just moved back and forth so I used nebconverge.pl to generate the force. And as seen in the ...