[Phonopy-users] Using Phonopy
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From: Ashish B. <ash...@gm...> - 2015-11-09 10:03:03
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Hi all, I need your kind help in calculating Phonon DOS for my system I have relaxed my structure using the following tags in vasp NCORE = 8 Startparameter for this Run: NWRITE = 1 (LPETIM=F write-flag & time) ISTART = 0 !0=new, 1=wave, 2=same cutoff&latt (1&2 need WAVECAR # ICHARG = 0 !0=charge from wave, 1=charge from CHGCAR, 2=atom # ISPIN = 2 LWAVE = .FALSE. (TRUE-Write WAVECAR, FALSE-not) LCHARG = .FALSE. (TRUE-Write CHGCAR and CHG, FALSE-not) GGA = PE Electronic Relaxation ENCUT = 525.0 PREC = Accurate !Medium=default, Low, High; affects ENMAX, mesh, pspot EDIFF = 1E-8 !energy stopping-criterion for electr. iterations EDIFFG = -0.0001 !force stopping-criterion for geometry steps Ionic Relaxation NSW = 500 !max number of geometry steps NELM = 200 NELMDL = -12 IBRION = 1 !ionic relax: 0-MD 1-quasi-New (RMM-DIIS for NEB) ISIF = 2 !(0:force=y stress=n ions=y shape=n volume=n, # 1:f=y s=diag i=y s=n v=n, 4:f=y s=y i=y s=y v=n, 5:f=y s=y i=n s=y v=n) ISYM = 1 !1=use symmetry, 0 = no symmetry #POTIM = .25 !initial time step for geo-opt (increase for soft sys) DOS related values: ISMEAR = 1 ! -4-tet -1-fermi 1=Methfessel/Paxton 1.order SIGMA = .05 !broadening in eV Electronic Relaxation ALGO = Normal # IALGO = 48 !algorithm (8=CG for small, 48=RMM for big systems) LREAL = FALSE !real-space projection After that I move CONTCAR to POSCAR and want to use phonopy So I simply change IBRION=1 to IBRION=8. in my INCAR. Now at some places I found NSW=1 with IBRION=8 for calculating Phonon DOS using Phonopy. So should I set NSW=500 or should I use NSW=1? Also please tell me whether EDIFF=1E-8 and EDIFFG=-0.0001 is sufficient condition for phonopy if not then how should i check the optimum condition? Thanks -- Ashish Bhatnagar Senior Research Fellow Hydrogen Energy Centre, Dept. of Physics Banaras Hindu University, Varanasi India - 221005 |