Hello Matt, Can I introduce some broadening, keeping in mind this structure is semiconductor no metallic?
Thanks IYAD On Wed, Aug 15, 2012 at 1:38 PM, Matthijs Mentink <mgtmentink at lbl.gov>wrote: > Hi Iyad, > > Have you considered introducing some broadening in the pwscf calculation? > It helps. Be careful not to go overboard though. You could try introducing > some broadening (like 1e-3 Ry or so) and see if it converges. If that works > than you can see how far you can reduce broadening while still having the > phonon calculations converge. > > cheers, > > Matthijs > > > On Wed, Aug 15, 2012 at 10:27 AM, Iyad AL-QASIR <iyad.ne at gmail.com> wrote: > >> Hi Wiliam, >> >> I used tr2_ph = 1.0d-10, it did not converge either after 100 steps. The >> |ddv_scf|^ values are about ~ E-07. >> >> However, when I used tr2_ph = 1.0d-14, the |ddv_scf|^ values are >> diverging strongly ~E+20 and even more. >> >> Kindest Regards, >> >> >> >> >> On Fri, Aug 10, 2012 at 5:16 PM, William Parker <wparker at anl.gov> wrote: >> >>> Hi Iyad, >>> >>> How strong is the failure to converge at (0, 1/6, 1/6)? Perhaps a less >>> tight tr2_ph value of, say, 1.0d-10 would get you where you need to be. >>> >>> --William >>> >>> On Aug 10, 2012, at 12:29 PM, Iyad AL-QASIR wrote: >>> >>> > Dear PW_Forum, >>> > >>> > I am running phonon calculations for FeSi (a narrow band gap >>> semiconductor) using QE-5.0. I am using a 6x6x6 q-vectors mesh. The first 4 >>> q-points ran successfully and got good phonon values. However when I reach >>> the 5th point(0 1/6 1/6). The self-consistent calculations do not converge. >>> I tried to reduce alpha_mix(1) to 0.3 but still have the same problem. >>> > >>> > Below are my input files: >>> > >>> > &control >>> > calculation='scf', >>> > restart_mode='from_scratch', >>> > title='FeSi', >>> > outdir='./', >>> > prefix='FeSi', >>> > pseudo_dir='./', >>> > / >>> > &system >>> > ibrav=1, >>> > celldm(1)=8.4165, >>> > nat=8, ntyp=2, >>> > ecutwfc=60.0, >>> > ecutrho= 720.0, >>> > / >>> > &electrons >>> > conv_thr=1.0d-9, >>> > mixing_mode='plain', >>> > mixing_beta=0.7, >>> > diagonalization='david', >>> > / >>> > ATOMIC_SPECIES >>> > Fe 55.847 Fe.pw91-sp-van_ak.UPF >>> > Si 28.086 Si.pw91-n_van.UPF >>> > ATOMIC_POSITIONS >>> > Fe 0.134855265 0.134855265 0.134855265 >>> > Fe 0.634855265 0.365144735 0.865144735 >>> > Fe 0.865144735 0.634855265 0.365144735 >>> > Fe 0.365144735 0.865144735 0.634855265 >>> > Si 0.839976366 0.839976366 0.839976366 >>> > Si 0.339976366 0.660023634 0.160023634 >>> > Si 0.160023634 0.339976366 0.660023634 >>> > Si 0.660023634 0.160023634 0.339976366 >>> > K_POINTS {automatic} >>> > 10 10 10 0 0 0 >>> > *********************************** >>> > phonons of FeSi >>> > &inputph >>> > tr2_ph=1.0d-14, >>> > prefix='FeSi', >>> > amass(1)=55.847, >>> > amass(2)=28.086, >>> > outdir='./' >>> > fildyn='FeSi.dyn', >>> > trans=.true., >>> > ldisp=.true., >>> > nq1=6, nq2=6, nq3=6 >>> > recover=.true., >>> > alpha_mix(1)=0.30 >>> > >>> > Any comments and suggestions are welcomed. >>> > >>> > Thanks >>> > IYAD >>> > >>> > >>> > _______________________________________________ >>> > Pw_forum mailing list >>> > Pw_forum at pwscf.org >>> > http://www.democritos.it/mailman/listinfo/pw_forum >>> >>> ********************************************************* >>> William D. Parker phone: (630) 252-4834 >>> Computational Postdoctoral Fellow fax: (630) 252-4798 >>> MSD-212, Rm. C-215 >>> Argonne National Laboratory >>> 9700 S. Cass Ave. >>> Argonne, IL 60439 >>> ********************************************************* >>> >>> >>> >>> >>> >>> _______________________________________________ >>> Pw_forum mailing list >>> Pw_forum at pwscf.org >>> http://www.democritos.it/mailman/listinfo/pw_forum >>> >> >> >> >> -- >> ___________________________ >> IYAD I. AL-QASIR, PhD >> Postdoc Research Associate >> >> X-Ray and Neutron Scattering and Spectroscopy Group >> Materials Science and Technology Division >> Oak Ridge National Lab >> Oak Ridge, TN >> >> >> _______________________________________________ >> Pw_forum mailing list >> Pw_forum at pwscf.org >> http://www.democritos.it/mailman/listinfo/pw_forum >> >> > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > > -- ___________________________ IYAD I. AL-QASIR, PhD Postdoc Research Associate X-Ray and Neutron Scattering and Spectroscopy Group Materials Science and Technology Division Oak Ridge National Lab Oak Ridge, TN -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120815/1711e896/attachment-0001.htm