The absence of the COHPCAR.lobster file after running a LOBSTER calculation indicates an issue during the LOBSTER execution. Since LOBSTER does not report errors as clearly as VASP, the problem might arise from either input file issues or insufficient preconditions being met during the VASP calculation.

Here are potential reasons and solutions to why COHPCAR.lobster is not generated:

Issues with lobsterin Keywords

The keyword OHPstartEnergy appears to be misspelled. The correct keyword is COHPstartEnergy.

OHPstartEnergy -10

With:

COHPstartEnergy -10

Basis Set Issue

You are using pbeVaspFit2015 as the basis set. Ensure that this basis set is compatible with the pseudopotentials used in your VASP calculation. If there's a mismatch between pseudopotential files and the chosen basis set, LOBSTER may fail.

Verify that the pseudopotentials in your POTCAR file correspond to the basis set pbeVaspFit2015. If in doubt, you can try a different basis set:

usebasisset pbeVaspFit2018

WAVECAR,

LOBSTER requires the WAVECAR file to reconstruct the COHP. If this file is missing or incomplete, LOBSTER will fail.

Check that the VASP calculation finished properly and that a valid WAVECAR file exists.

Double-check the NBANDS: LOBSTER requires all relevant bands to be present in the WAVECAR. If NBANDS is too low, important bands may be missing.

NBANDS

The number of bands specified in NBANDS may not be sufficient for LOBSTER to reconstruct the COHP properly.

Increase the number of bands in the VASP run, especially if the system involves heavy elements with high energy states:

NBANDS = 1000

Rerun the VASP calculation to regenerate WAVECAR.

Incomplete Pair Selection in cohpbetween

The keyword cohpbetween atom 1 and atom 2 might refer to atoms that do not have meaningful bonds, or the indices might be invalid.

Verify the indices of atoms 1 and 2 using a visualization tool (VESTA) to confirm that these atoms are bonded.

Use a broader range for testing initially, like:

cohpbetween atom 1 and all

Check for LOBSTER Log Files

Solution:

Review the lobster.out file for error messages. This file will give clues about what went wrong during the LOBSTER execution.

Ensure VASP Output is Sufficient

LOBSTER requires a clean WAVECAR, CHGCAR, and POSCAR file.

Look after if,

The VASP run terminated normally.

CHGCAR is written and not corrupted.

ISIF = 0 is fine for static calculations, but ensure no relaxation or dynamic runs are performed.

Corrected lobsterin File

Here is an updated and corrected version of your lobsterin file:

COHPstartEnergy -10

COHPendEnergy 6

usebasisset pbeVaspFit2018

includeOrbitals s p d

basisfunctions Pb 5d 6p

basisfunctions O sp

basisfunctions H sp

basisfunctions I 5s 5p

cohpbetween atom 1 and all

Rerun VASP with corrected NBANDS and LWAVE settings.

After VASP completes, confirm that WAVECAR, CHGCAR, and POSCAR are correctly generated and uncorrupted.

Run LOBSTER and monitor lobster.out for errors.

I hope this can help

Thank you Mustapha Lasmi