Hi Iyad,<br><br>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.<br>
<br>cheers,<br><br>Matthijs<br><br><div class="gmail_quote">On Wed, Aug 15, 2012 at 10:27 AM, Iyad AL-QASIR <span dir="ltr"><<a href="mailto:iyad.ne@gmail.com" target="_blank">iyad.ne@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi Wiliam,<br><br>I used tr2_ph = 1.0d-10, it did not converge either after 100 steps. The |ddv_scf|^ values are about ~ E-07. <br>
<br>However, when I used tr2_ph = 1.0d-14, the |ddv_scf|^ values are diverging strongly ~E+20 and even more.<br>
<br>Kindest Regards,<div class="im HOEnZb"><br><br><br><br>On Fri, Aug 10, 2012 at 5:16 PM, William Parker <span dir="ltr"><<a href="mailto:wparker@anl.gov" target="_blank">wparker@anl.gov</a>></span> wrote:<br></div>
<div class="HOEnZb"><div class="h5"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi Iyad,<br>
<br>
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.<br>
<br>
--William<br>
<div><div><br>
On Aug 10, 2012, at 12:29 PM, Iyad AL-QASIR wrote:<br>
<br>
> Dear PW_Forum,<br>
><br>
> 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.<br>
><br>
> Below are my input files:<br>
><br>
> &control<br>
> calculation='scf',<br>
> restart_mode='from_scratch',<br>
> title='FeSi',<br>
> outdir='./',<br>
> prefix='FeSi',<br>
> pseudo_dir='./',<br>
> /<br>
> &system<br>
> ibrav=1,<br>
> celldm(1)=8.4165,<br>
> nat=8, ntyp=2,<br>
> ecutwfc=60.0,<br>
> ecutrho= 720.0,<br>
> /<br>
> &electrons<br>
> conv_thr=1.0d-9,<br>
> mixing_mode='plain',<br>
> mixing_beta=0.7,<br>
> diagonalization='david',<br>
> /<br>
> ATOMIC_SPECIES<br>
> Fe 55.847 Fe.pw91-sp-van_ak.UPF<br>
> Si 28.086 Si.pw91-n_van.UPF<br>
> ATOMIC_POSITIONS<br>
> Fe 0.134855265 0.134855265 0.134855265<br>
> Fe 0.634855265 0.365144735 0.865144735<br>
> Fe 0.865144735 0.634855265 0.365144735<br>
> Fe 0.365144735 0.865144735 0.634855265<br>
> Si 0.839976366 0.839976366 0.839976366<br>
> Si 0.339976366 0.660023634 0.160023634<br>
> Si 0.160023634 0.339976366 0.660023634<br>
> Si 0.660023634 0.160023634 0.339976366<br>
> K_POINTS {automatic}<br>
> 10 10 10 0 0 0<br>
> ***********************************<br>
> phonons of FeSi<br>
> &inputph<br>
> tr2_ph=1.0d-14,<br>
> prefix='FeSi',<br>
> amass(1)=55.847,<br>
> amass(2)=28.086,<br>
> outdir='./'<br>
> fildyn='FeSi.dyn',<br>
> trans=.true.,<br>
> ldisp=.true.,<br>
> nq1=6, nq2=6, nq3=6<br>
> recover=.true.,<br>
> alpha_mix(1)=0.30<br>
><br>
> Any comments and suggestions are welcomed.<br>
><br>
> Thanks<br>
> IYAD<br>
><br>
><br>
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</blockquote></div><br><br clear="all"><br></div></div><span class="HOEnZb"><font color="#888888">-- <br>___________________________<br>IYAD I. AL-QASIR, PhD<br>Postdoc Research Associate <br><br>X-Ray and Neutron Scattering and Spectroscopy Group<br>
Materials Science and Technology Division<br>
Oak Ridge National Lab<br>Oak Ridge, TN<br><br>
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