<div dir="ltr"><div id="gmail-:2sg" class="gmail-ii gmail-gt" style="direction:ltr;margin:8px 0px 0px;padding:0px"><div id="gmail-:2sf" class="gmail-a3s gmail-aXjCH" style="overflow:hidden;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;line-height:1.5"><div dir="ltr" style=""><div style=""><font face="arial, sans-serif" style="">Hello users,</font></div><div style=""><font face="arial, sans-serif" style=""><br></font><div style=""><font face="arial, sans-serif"><span style="color:rgb(29,28,29);font-variant-ligatures:common-ligatures;background-color:rgb(248,248,248)">I have been trying to simulate graphene phonon dispersion using DFT-DF2 vdW functional and ONCV pseudopotential.</span></font></div><div style=""><font face="arial, sans-serif"><br style="box-sizing:inherit;color:rgb(29,28,29);font-variant-ligatures:common-ligatures;background-color:rgb(248,248,248)"><span style="color:rgb(29,28,29);font-variant-ligatures:common-ligatures;background-color:rgb(248,248,248)">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. </span>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. <span style="background-color:rgb(248,248,248);color:rgb(29,28,29);font-variant-ligatures:common-ligatures">Can someone point out the error?</span></font></div></div><div style=""><font face="arial, sans-serif"><br></font></div><div style=""><font face="arial, sans-serif">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 <a href="https://drive.google.com/drive/folders/1KVlLz6SoTpTdxcviNTyEvMAKrOJb1ZyM?usp=sharing">link</a> - </font><a href="https://drive.google.com/drive/folders/1KVlLz6SoTpTdxcviNTyEvMAKrOJb1ZyM?usp=sharing">https://drive.google.com/drive/folders/1KVlLz6SoTpTdxcviNTyEvMAKrOJb1ZyM?usp=sharing</a></div><div style=""><br></div><div style=""><font face="arial, sans-serif">Thank you very much.</font></div><div style=""><font face="arial, sans-serif"><br></font></div><div style=""><font face="arial, sans-serif">Best Regards,</font></div><div style=""><font face="arial, sans-serif">Dhvaneel Visaria</font></div><div style=""><font face="arial, sans-serif">IIT Bombay</font></div></div><div class="gmail-yj6qo" style=""></div><div class="gmail-adL" style=""></div></div></div><div class="gmail-hq gmail-gt" id="gmail-:2us" style="margin:15px 0px;clear:both"><font face="arial, sans-serif"><u>Pseudopotential file:</u></font></div><div class="gmail-hq gmail-gt" id="gmail-:2us" style="margin:15px 0px;clear:both"><UPF version="2.0.1"><br>  <PP_INFO><br>    Generated using "atomic" code by A. Dal Corso  v.5.0.99 svn rev. 10869<br>    Author: TM<br>    Generation date: 10Apr2014<br>    Pseudopotential type: NC<br>    Element:  C<br>    Functional: REVPBE<font face="arial, sans-serif"><br></font></div><div class="gmail-hq gmail-gt" id="gmail-:2us" style="margin:15px 0px;clear:both"><span style="font-family:arial,sans-serif"><br></span></div><div class="gmail-hq gmail-gt" id="gmail-:2us" style="margin:15px 0px;clear:both"><span style="font-family:arial,sans-serif"><u>The input to the pw.x is as follows:</u></span><br></div><div class="gmail-hq gmail-gt" id="gmail-:2us" style="margin:15px 0px;clear:both"><font face="arial, sans-serif"> &control<br>  title='MyTitle'<br>  calculation='scf'<br>  restart_mode='from_scratch'<br>  outdir='/scratch/MatSim//dfpt_24_24_137407890'<br>  pseudo_dir='/home/MatSim/dhvaneel.visaria/VDW/graphene/df2/'<br>  prefix='dfpt_24_24_137407890'<br>  tprnfor=.true.<br>  tstress=.true.<br> /<br><br> &system<br>  ibrav=0<br>  nat=2<br>  ntyp=1<br>  ecutwfc=100.00<br>  occupations='smearing'<br>  smearing='gaussian'<br>  degauss=0.01<br>  input_dft='vdw-df2'<br> /<br><br> &electrons<br>  conv_thr=1.0d-12<br>  mixing_beta=0.1<br> /<br><br> &IONS<br>  <br> /<br><br> &CELL<br> /<br><br> ATOMIC_SPECIES<br>  C  12.01 C.UPF<br> <br><br> ATOMIC_POSITIONS angstrom<br>  C  0.0000000000 0.0000000000 0.0000000000<br>  C  1.2370000000 0.7141822830 0.0000000000<br> <br><br> K_POINTS automatic<br>  12 12 1 0 0 0<br> <br><br> CELL_PARAMETERS Angstrom<br>  1.2370000000 -2.1425468490 0.0000000000<br>  1.2370000000 2.1425468490 0.0000000000<br>  0.0000000000 0.0000000000 12.0000000000 </font></div><div class="gmail-hq gmail-gt" id="gmail-:2us" style="margin:15px 0px;clear:both"><font face="arial, sans-serif"><u>The input to ph.x is as follows:</u></font></div><div class="gmail-hq gmail-gt" id="gmail-:2us" style="margin:15px 0px;clear:both"><font face="arial, sans-serif"> title='MyTitle'<br></font></div><font face="arial, sans-serif"> &inputph<br>  tr2_ph=1.0d-18<br>  niter_ph=200<br>  nmix_ph=8<br>  alpha_mix(1)=0.3<br>  ldisp=.true.<br>  search_sym=.true.<br>  trans=.true.<br>  nq1=24<br>  nq2=24<br>  nq3=1<br>  prefix='dfpt_24_24_137407890'<br>  fildyn='dfpt.dyn'<br>  outdir='/scratch/MatSim//dfpt_24_24_137407890'<br> /<br></font><br></div>