Hello users, I have been trying to simulate graphene phonon dispersion using DFT-DF2 vdW functional and ONCV pseudopotential.
I am using input_dft=‘vdw-df2’. I am getting nice convergence with scf calculations using pw.x but I am unable to achieve convergence despite all adjustments to the numerical parameters (nmix_ph, alpha_mix, max_iter) using ph.x. I have also recompiled QE after adjusting max_iter and ndim_mix to allow max iterations beyond 100 and ndim_mix greater than 5 but to no avail. I think that there could be an issue with the way I am trying to use input_dft/PP for vdW-df2. Can someone point out the error? The PP header and input to the pw.x & ph.x can be found at the end for reference while the output files can be found in this link <https://drive.google.com/drive/folders/1KVlLz6SoTpTdxcviNTyEvMAKrOJb1ZyM?usp=sharing> - https://drive.google.com/drive/folders/1KVlLz6SoTpTdxcviNTyEvMAKrOJb1ZyM?usp=sharing Thank you very much. Best Regards, Dhvaneel Visaria IIT Bombay *Pseudopotential file:* <UPF version="2.0.1"> <PP_INFO> Generated using "atomic" code by A. Dal Corso v.5.0.99 svn rev. 10869 Author: TM Generation date: 10Apr2014 Pseudopotential type: NC Element: C Functional: REVPBE *The input to the pw.x is as follows:* &control title='MyTitle' calculation='scf' restart_mode='from_scratch' outdir='/scratch/MatSim//dfpt_24_24_137407890' pseudo_dir='/home/MatSim/dhvaneel.visaria/VDW/graphene/df2/' prefix='dfpt_24_24_137407890' tprnfor=.true. tstress=.true. / &system ibrav=0 nat=2 ntyp=1 ecutwfc=100.00 occupations='smearing' smearing='gaussian' degauss=0.01 input_dft='vdw-df2' / &electrons conv_thr=1.0d-12 mixing_beta=0.1 / &IONS / &CELL / ATOMIC_SPECIES C 12.01 C.UPF ATOMIC_POSITIONS angstrom C 0.0000000000 0.0000000000 0.0000000000 C 1.2370000000 0.7141822830 0.0000000000 K_POINTS automatic 12 12 1 0 0 0 CELL_PARAMETERS Angstrom 1.2370000000 -2.1425468490 0.0000000000 1.2370000000 2.1425468490 0.0000000000 0.0000000000 0.0000000000 12.0000000000 *The input to ph.x is as follows:* title='MyTitle' &inputph tr2_ph=1.0d-18 niter_ph=200 nmix_ph=8 alpha_mix(1)=0.3 ldisp=.true. search_sym=.true. trans=.true. nq1=24 nq2=24 nq3=1 prefix='dfpt_24_24_137407890' fildyn='dfpt.dyn' outdir='/scratch/MatSim//dfpt_24_24_137407890' /
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