UT theoretical chemistry code forum

Dear all,

i am getting this error in my NEB calculation - Error reading item 'IOPT' from file INCAR.

The following is my INCAR file:
System = CO plus OH on Ni(100)

ISTART = 0
NWRITE = 3

EDIFF = 1e-4 # electronic convergence
PREC = High
ENCUT = 400
IBRION = 3
POTIM = 0.0
NSW = 200
EDIFFG = -0.1 # max forces: 0.1eV/AA
IMAGES = 8 # 8 intermediate geometries for
LCLIMB = .TRUE.
IOPT = 1 # LBFGS = Limited-memory Broyden-Fletcher-Goldfarb-Shanno
ICHAIN = 0
INVCURV = 0.002
LTANGENTOLD = .FALSE.
LDNEB = .FALSE.
NEBCELL = .FALSE.
SPRING = -5 # spring constant
ISPIN = 2
GGA = RP


#LWAVE = False
#LCHARG = False

NCORE = 192
KPAR = 4

Could anyone please let me know what could be the reason for this and how can I over come it.

Thanks,
Mmg016

Make sure that the vtstcode is linked into your vasp binary. You can grep the OUTCAR for VTST to see if it reports the version number.

Dear Prof. Henkelman,

Thank you for your reply.
I have grepped for 'VTST' in the OUTCAR of a calculation in which LCLIMB was set to be true. The response I got was, "VTST: version 3.1, (03/28/14)".
This indicates that VTST code is already built into my vasp binary. However, 'IOPT" reading error remains persistent.

Is it a possibility that the VTST code is not PROPERLY built into my vasp binary? I mean, there are two parts to building VTST into vasp source. One is, making changes into main.F file, and the second is to include your code files and add those objects in the Makefile. Is it possible that VTST still shows 'false positive' (VTST: version 3.1, (03/28/14)) while may be first or the second task from these has not correctly been performed.

Thank you for your time.

mmg016

If you can post a .tar.gz file of the calculation, I can try to reproduce the error and debug it.

Dear Prof. Henkelman,

Thank you for your time and efforts.

I have attached the .tar.gz of the calculation with positive result. There is also the incar in this archive which is giving me the error.

Best regards,
mmg016

remove the two tabs after IOPT = 1 in your INCAR file

Thank you for pointing my (so silly!) mistake. The calculation is now running.

mmg016

Dear Prof. Henkelman,
I have a simillar problem (i.e. IOPT error).

I have tested all the solutions you provided. It seems the vasp built with VTST is fine, according to your explanation here. Mine is "VTST: version 3.2, (02/03/18)".

I would appreciate your help with this. I have attached the .zip of my calculations.

Many thanks for considering my request.

Kind regards,
Ganesh K Nayak
RWTH Aachen

IOPT should be an integer; I see it set as 0.2 in your INCAR.

Dear Prof. Henkelman,
Thank you for the hint.

Kind regards,
Ganesh K Nayak