[QE-users] Phonon calculation does not converge

[Nicola Marzari]

Out of curiosity, wouldn’t a low cutoff (not that one should use it) miss a ghost state (that is very localized)?

In passing, sssp pseudos are tested re not having ghosts, and have default suggested cutoffs. Just make sure you use the latest version 1.3

Nicola

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On 23 Jan 2024, at 09:02, Lorenzo Paulatto <lorenzo.paulatto at cnrs.fr> wrote:



The calculation is not only not converging, it is actually diverging. Changing alpha_mix and increasing nmix_ph can help, but it may also indicate something wrong with the calculation. I.e. a metal treated as semiconductor, or a ghost in the pseudopotential (which may be likely if you use norm-conservig cutoff with an ultrasoft dataset)

hth


On 1/23/24 08:47, Chirantan Pramanik wrote:
Hello All,

I was running Phonon for a few systems of carbonate minerals for a long time. Recently I used SSSP pseudopotential for PBE and faced a problem like the one pasted below. Optimization and SCF calculations are properly done. But phonon calculation is not converging. Please help. I think changing alpha_mix can be useful, but for my stable and optimized system, it should converge easily.

section from ph.x output:

      iter #  97 total cpu time :  1799.1 secs   av.it.:  84.0
      thresh= 1.000E-02 alpha_mix =  0.700 |ddv_scf|^2 =  1.595E+08

      iter #  98 total cpu time :  1822.7 secs   av.it.:  92.0
      thresh= 1.000E-02 alpha_mix =  0.700 |ddv_scf|^2 =  3.870E+10

      iter #  99 total cpu time :  1846.5 secs   av.it.:  92.0
      thresh= 1.000E-02 alpha_mix =  0.700 |ddv_scf|^2 =  4.585E+10

      iter # 100 total cpu time :  1869.3 secs   av.it.:  88.0
      thresh= 1.000E-02 alpha_mix =  0.700 |ddv_scf|^2 =  5.897E+09

     End of self-consistent calculation

     No convergence has been achieved


Please help in this regard.

Thanks and Regards,
Chirantan

Chirantan Pramanik
Postdoctoral Researcher
Dept. of Earth and Planetary Sciences
Weizmann Institute of Science
Rehovot, Israel



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