[QE-users] Query regarding ecutfock

[Lorenzo Bastonero]

Dear Arini,

You should do some test first in the pristine unit cell structure before going forward to the supercell calculations. 

In principle, you could lower down even more that cutoff (and the qpoint for the fock operator as well). Usually a good threshold is ~10^-5 Ry/bohr on every atomic force component.

Note: this threshold is different from the one of the relax. So you should check that when changing your variables (ecutfock in this case) all your forces don’t change within this threshold.

HTH,
Lorenzo 

Inviato da iPhone

> Il giorno 11 apr 2023, alle ore 20:45, Arini Kar via users <users at lists.quantum-espresso.org> ha scritto:
> 
> 
> Dear users,
> 
> I am trying to run phonon calculations using phonopy. I am using norm conserving pseudopotential. Can I use ecutfock = 2*ecutwfc instead of the default value in the scf calculations? Would it affect the accuracy of force calculations?
> 
> Thanking you.
> 
> Regards
> 
> Arini Kar
> 
> PhD student 
> 
> Indian Institute of Technology Bombay, India
> 
> 
> 
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