UT theoretical chemistry code forum

hi,
I am still struggling with my ss-NEB calculation. I ran a regular NEB calculation to verify that the vasp version I am using works fine. With the ss-NEB flags turned on, however, my jobs never converge or it do not run at all. I was playing different flags, but no success.
Could you please post ...

hi,
What do you mean by "these results are strange: the distance between the initial and final states is 0 and images are so close"? The four columns I am showing represent images, forces, energies, barrier obtained with the nebef.pl script. They are not the same structure. I am not sure why you ...

hi,
thanks for your reply. ICHAIN=0 did not help per se as it is set by default. However, I set the FMAGFLAG=T flag and I can tell that the optimization proceeds by observing changes in the cell volumes for each image. However, I still have a problem with the job because it does not converge (kind ...

Yes, about 2 weeks ago.

Yes, it is.

Hello,
thanks for your reply. I appreciate your time.
However, I don't think my calculations are correct. I just checked that the energies I get from the SS-NEB run are identical to single point (no relaxation) energies for my images, which implies that no shape/volume optimization was performed ...

hi,
Thank you for your quick response. It seems like the POTIM =0.0 flag helped to get rid of the "internal ERROR: DEPLE: IRDMAX" problem. However, I am not sure if my job is correct for two reasons: First, in the CONTCAR files after the two lines giving atoms' direct coordinates, I find some ...

hi,
Below is the INCAR. I greatly appreciate your help.
============================================
SYSTEM = R.S.
NWRITE = 1
ISTART = 0

ENCUT = 400.0 eV
PREC = HIGH
EDIFF = 1E-05
EDIFFG = -1E-03

LCORR = T
IBRION = 3
NSW = 100
ISYM = 0

ISMEAR = 0; SIGMA = .01
IALGO = 38
LDIAG ...

hi,
I was trying to run NEB with ISIF=3 flag for a relatively simple system with 2 atoms in the unit cell. The job went through 3 ionic iterations, but then it stopped giving the following is the error message:
internal ERROR: DEPLE: IRDMAX must be increased to 275
internal ERROR: DEPLE: IRDMAX ...

Thank you for replying to my question.
When running NEB with ISIF=3, is it necessary to set the PSTRESS flag (in what units)?
If not, is PSTRESS=0 the default value?
Thanks.

Do I have to use a specific version of VTST?
Also, I am a bit confused about LNEBCELL flag. Could you please define it for me?
Thanks.

hi,
can we run NEB calculations with ISIF=4 in VASP (that is relaxing ions and allowing cell shape to change at constant volume) or ISIF=3 (allowing ions to move, and cell shape and volume to change as well)?
If it is possible, is there any flag I should be paying attention to?
I would appreciate ...

Thank you.

hello,
thanks for your quick reply to my question. Could you please elaborate a bit more about the weighted average flag? What exactly is it doing?
In the code, $cut=0.25*$maxDOS. I am not sure how this is related to the integration limits of the d-band. I would greatly appreciate your help.
Thanks.

hi,
I am using the dosanalyze.pl script to calculate the d-band center for my system. Setting the weighted average flag to 2.5 (default) gives me 1.6 eV for the d-band center. However, when I change w to 2.0, I get 1.79 eV. Using w=3.0, in turn, gives me 1.52 eV. What is the reasonable value for w ...