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Hi,

Is the energy output (e_0_energy) from Berry phase calculation under finite electric field (LCALCPOL = .TRUE.) the electric enthalpy (\(E_0 - \Omega \mathcal{\boldsymbol E} \cdot \mathbf{P}\)) or the system internal energy (first term \(E_0\) on the RHS of electric enthalpy functional in doc https://www.vasp.at/wiki/index.php/Berr ... ric_fields?

Based on doc, VASP minimize the electric enthalpy functional but I didn't see its output. I think it makes more sense if e_0_energy is system's internal energy but would like to confirm.

Thanks,
Yuan

Hi Yuan,

Thanks for reaching out. In VASP, the \(E_0\) that you see there is the total free energy, which is minimized during the electronic DFT self-consistency cycle. Keep in mind that the total energy calculated by VASP still depends on ISMEAR and SIGMA.

Hi,

Thanks for the reply but it is still not clear to me. Does the e_0_energy contain \(-\Omega \mathbf{E} \cdot \mathbf{P}\) or not?

No worries. I'm happy to clarify my previous statement. The total energy, which is the e_0_energy that you refer to, does not include the \(-\Omega \mathbf{E} \cdot \mathbf{P}\) term.

Let me know if that answers your question.

Yes. Thanks so much for the clarification!