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LMBJ for 1D system
Posted: Thu Mar 26, 2026 2:44 pm
by subrata
Hi,
I have a problem with LMBJ calculations for 1D systems. For example
C6H4
1.00
11.0000000 0.00000000 0.00000000
0.00000000 18.0000000 0.00000000
0.00000000 0.00000000 4.25370598
C H
6 4
Direct
1.66417228E-03 2.35353783E-03 3.46985529E-03
1.24619855E-03 -6.47786558E-02 0.171479195
1.23689917E-03 -6.47874400E-02 0.495433241
1.65815942E-03 2.35325214E-03 0.663318634
2.24087597E-03 6.94881454E-02 0.171472147
2.24125758E-03 6.95001483E-02 0.495434552
1.07410457E-03 -0.118248492 4.89231870E-02
1.05037668E-03 -0.118312985 0.617444932
2.87996116E-03 0.122985058 4.90232334E-02
2.88981409E-03 0.123051353 0.617333829
The band gaps seem very wrong. Any suggestions on how to do the correct calculations
Subrata
Re: LMBJ for 1D system
Posted: Fri Mar 27, 2026 11:04 am
by max_liebetreu
Hello subrata,
Thanks for reaching out to us on the VASP Forums!
We can gladly take a look - please provide a minimal reproducible example containing the relevant files for your calculation.
Could you please offer some more details about the issue you are seeing with the bandgaps?
Best regards,
Max
Re: LMBJ for 1D system
Posted: Fri Mar 27, 2026 2:28 pm
by subrata
Here is the INCAR file for LMBJ calculation
Code: Select all
EDIFF = 1E-5
ISMEAR = 0
SIGMA = 0.05
NELM = 1000
ALGO = A
IMIX = 1
AMIX = 0.4
AMIN = 0.01
LASPH = .TRUE.
METAGGA = LMBJ
SMBJ = 2.0
RSMBJ = 7.0
CMBJA = 0.488
CMBJB = 0.5
CMBJE = 1.0
and Here is the POSCAR file
Code: Select all
C6H4
1.00
11.0000000 0.00000000 0.00000000
0.00000000 18.0000000 0.00000000
0.00000000 0.00000000 4.25370598
C H
6 4
Direct
1.66417228E-03 2.35353783E-03 3.46985529E-03
1.24619855E-03 -6.47786558E-02 0.171479195
1.23689917E-03 -6.47874400E-02 0.495433241
1.65815942E-03 2.35325214E-03 0.663318634
2.24087597E-03 6.94881454E-02 0.171472147
2.24125758E-03 6.95001483E-02 0.495434552
1.07410457E-03 -0.118248492 4.89231870E-02
1.05037668E-03 -0.118312985 0.617444932
2.87996116E-03 0.122985058 4.90232334E-02
2.88981409E-03 0.123051353 0.617333829
The band gap I am getting from LMBJ OUTCAR is
Code: Select all
val. band max: 46.4875371038 @ k = 0.0000 0.0000 0.0000
cond. band min: 26.6582385172 @ k = 0.0000 0.0000 0.3000
fundamental gap: -19.8292985866
Fermi energy: ********************
I am using regular PBE C and H pseudopotential
Re: LMBJ for 1D system
Posted: Fri Mar 27, 2026 3:22 pm
by max_liebetreu
Thank you, that helps us understand your setup.
I will discuss this with my colleagues, and we will get back to you on Monday.
Re: LMBJ for 1D system
Posted: Mon Mar 30, 2026 8:55 am
by manuel_engel1
Hello Subrata,
I have taken a look at your calculation with the information you have shared. Unfortunately, I am unable to reproduce your problem. The energies on my end appear reasonable. Please, upload as a zip archive the following files of the failing run:
The OUTCAR file in particular will be required for me to understand what goes wrong in your calculation.
Re: LMBJ for 1D system
Posted: Mon Mar 30, 2026 11:49 am
by subrata
I am attaching full files for a look.
Re: LMBJ for 1D system
Posted: Mon Mar 30, 2026 5:49 pm
by manuel_engel1
Thank you very much. I was able to confirm that this is an issue with VASP 6.4.3 that does not exist in the latest release version VASP 6.6.0. I'm very sorry for the inconvenience. If possible, I would urge you to upgrade your VASP version to the latest release. We are currently investigating whether this is a bug that exists also in other versions. If we find out more details, I will post them here as well.