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Dear VASP Admin,

According to the VASP Wiki, it is recommended to use GW potentials for optical calculations.

Is it possible to optimize the structure and perform all DFT and hybrid functional calculations—such as bandgap, DOS, and band structure—using the standard POTCAR files, and then perform a single-point calculation with the optimized structure and the relevant POTCAR_GW to evaluate only the optical properties?

Many thanks in advance,
Ibrahim

Dear Ibrahim,

I discussed this with my colleague and he agreed that this is in principle possible. However, to be on the safe side and have consistent results we would recommend to use the non-GW-POTCAR only for the structure optimization and use the GW-POTCAR for everything else (bandgap, DOS,..., optical properties). Also, make sure not to restart from an old WAVECAR file when switching the POTCAR files.

Best,
Andreas Singraber

Thanks for your helpful reply.

Although GW potentials are recommended for optical calculations, is it possible to use standard potentials also for optical calculations? What happened in this case?

Many thanks in advance,
Ibrahim

Hello!

Please have a look at the explanation just above the list of GW pseudopotentials here: wiki/index.php/Choosing_pseudopotential ... potentials. States well above the Fermi level are required for optical calculations and hence the regular pseudopotentials will not be sufficient.

Best,
Andreas Singraber

OK. thank you very much.

Ibrahim