Hi, I am trying to calculate full phonon dispersion with born effective charge. My ph.in file is -- Phonon Calcs for S1 &inputph prefix='S1' epsil=.true. ldisp=.true. verbosity='high' outdir='./home', fildyn='S1.888.dyn' nq1=8 nq2=8 nq3=8 /
When I use nq1,nq2,nq3 =4 , it generates 20 dynamical matrix file (.dyn), with nq1,nq2,nq3=8 it generates 35 files and so on with higher nq values.. Each .dyn file takes ~4 hrs on 100 core processor. My question is -- 1. Is there any procedure to know about nq values which will be okay to get a phonon dispersion with reliable accuracy. 2. Is there anything similar thing to do like we do a k-mesh convergence test for scf calculation in order to get a reliable electronic band structure. 3. Is nq and nk grid similar ? I tried to give all the information I could, I m new to QE so can't explain my doubts better than this, so, please update whatever possible. Thanks in advance Best, Kiran On Tue, Nov 3, 2020, 18:22 Lorenzo Paulatto <[email protected]> wrote: > > Is there any methodology to check and decide nq-grid points for phonon > > dispersion spectra calculations? > > I'm not sure what calculation you are trying to do. > Can you provide a more detailed description? > > Do not forget the second law of question-answer conservation: > «In a not-being-paid-for frame of reference, > the amount of time spent answering a question > will never exceed the amount of time spent asking it» > > > > -- > Lorenzo Paulatto - Paris > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users
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