I tried phonon calculation using the following tag in INCAR for a Double Perovskite material.
IBRION = -1, EDIFF = 1e-8, IALGO = 38, ISMEAR = 0, SIGMA = 0.05, ADDGRID = .TRUE, ENCUT = 350, LREAL = .FALSE, LWAVE = .FALSE, LCHARG = FALSE, PREC = Accurate. NELM = 150
But convergence is not achieved even after a lot of cycles. (attached screenshot)
Kindly suggest...
The githup file supplied by Nut is excellent, but it doesn't discuss conversion issues.
Yes, I would like to know how convergence can be achieved in phonon calculation. In the above-said GitHub link, only the phonon method is provided.
Hi Sumit Kukreti
Why you have used IBRION = -1 for phonon calculations? Try it with 6 or 8.
You can have a look at the answer by Selvarajan Premkumar to this question https://www.researchgate.net/post/How_to_perform_phonon_dispersion_calculations_using_VASP
It worked well almost for everyone. Hope it may help you too.
Hi, I think convergence is not related to phonons or phonopy. It is related VASP. As the atoms in the POSCARs are slightly displaced, it is facing the convergence issue. I suggest you to change IALGO = 38 as ALGO = All and check the convergence for one calculation. You can use IBRION = -1 if are not using DFPT.
Dear Sumit,
you can try to start from the WAVECAR that you obtain for your relaxed structure (or the corresponding supercell, i.e. the SPOSCAR file). As you only displace one atom this might help to achieve convergence. Depending on your system size this, however, costs you some memory.
- Badges
- Science method
- Similar topics
- Methodology
- Crystallography
- X-ray Diffraction