<div dir="ltr">Dear all,<div><br></div><div>I have read several posts regarding this issue but I am still unable to get the electrical fields calculation in ph.x converged for phonon dispersion calculation. The behavior, which many experience is as follows:</div><div><br></div><div><div> iter # 10 total cpu time : 21241.7 secs <a href="http://av.it">av.it</a>.: 1.3</div><div> thresh= 6.227E-05 alpha_mix = 0.400 |ddv_scf|^2 = <b>1.388E-08</b></div><div> iter # 11 total cpu time : 22225.5 secs <a href="http://av.it">av.it</a>.: 4.4<br></div><div> thresh= 1.178E-05 alpha_mix = 0.400 |ddv_scf|^2 = <b> 1.528E-12</b></div><div> iter # 12 total cpu time : 24354.9 secs <a href="http://av.it">av.it</a>.: 18.0<br></div><div> thresh= 1.236E-07 alpha_mix = 0.400 |ddv_scf|^2 = <b>3.025E-07</b></div><div> iter # 13 total cpu time : 25425.8 secs <a href="http://av.it">av.it</a>.: 5.7<br></div><div> thresh= 5.500E-05 alpha_mix = 0.400 |ddv_scf|^2 =<b> 6.748E-08</b></div><div> iter # 14 total cpu time : 26243.8 secs <a href="http://av.it">av.it</a>.: 2.9<br></div><div> thresh= 2.598E-05 alpha_mix = 0.400 |ddv_scf|^2 =<b> 2.569E-08</b></div><div> iter # 15 total cpu time : 27076.0 secs <a href="http://av.it">av.it</a>.: 3.3<br></div><div> thresh= 1.603E-05 alpha_mix = 0.400 |ddv_scf|^2 = 6.075E-08</div><div> iter # 16 total cpu time : 27797.8 secs <a href="http://av.it">av.it</a>.: 2.3<br></div><div> thresh= 2.465E-05 alpha_mix = 0.400 |ddv_scf|^2 = 3.101E-07</div><div> iter # 17 total cpu time : 29230.3 secs <a href="http://av.it">av.it</a>.: 9.7<br></div><div> thresh= 5.569E-05 alpha_mix = 0.400 |ddv_scf|^2 = 2.663E-07</div><div> iter # 18 total cpu time : 30358.8 secs <a href="http://av.it">av.it</a>.: 6.5<br></div><div> thresh= 5.160E-05 alpha_mix = 0.400 |ddv_scf|^2 = 3.309E-07</div><div> iter # 19 total cpu time : 31460.7 secs <a href="http://av.it">av.it</a>.: 6.0<br></div><div> thresh= 5.752E-05 alpha_mix = 0.400 |ddv_scf|^2 = 8.663E-08</div><div><br></div><div>that is, after originally apparently converging it starts oscillating between 1E-8 and 1E-7 until 100 iterations. Reducing alpha_mix down to 0.01 does not alleviate this problem.</div><div><br></div><div>Interestingly this does not happen for Gamma point only:</div><div><br></div><div><div> Electric Fields Calculation</div><div><br></div><div> iter # 1 total cpu time : 3714.8 secs <a href="http://av.it">av.it</a>.: 8.3</div><div> thresh= 1.000E-02 alpha_mix = 0.700 |ddv_scf|^2 = 1.982E-08</div><div> iter # 2 total cpu time : 5447.0 secs <a href="http://av.it">av.it</a>.: 19.2<br></div><div> thresh= 1.408E-05 alpha_mix = 0.700 |ddv_scf|^2 = 1.787E-08</div><div> iter # 3 total cpu time : 7174.1 secs <a href="http://av.it">av.it</a>.: 18.0<br></div><div> thresh= 1.337E-05 alpha_mix = 0.700 |ddv_scf|^2 = 1.003E-09</div><div> iter # 4 total cpu time : 8856.3 secs <a href="http://av.it">av.it</a>.: 18.0<br></div><div> thresh= 3.167E-06 alpha_mix = 0.700 |ddv_scf|^2 = 9.881E-11</div><div> iter # 5 total cpu time : 10554.6 secs <a href="http://av.it">av.it</a>.: 18.3<br></div><div> thresh= 9.940E-07 alpha_mix = 0.700 |ddv_scf|^2 = 1.223E-10</div><div> iter # 6 total cpu time : 12142.6 secs <a href="http://av.it">av.it</a>.: 16.9<br></div><div> thresh= 1.106E-06 alpha_mix = 0.700 |ddv_scf|^2 = 2.022E-12</div><div> iter # 7 total cpu time : 13919.5 secs <a href="http://av.it">av.it</a>.: 18.7<br></div><div> thresh= 1.422E-07 alpha_mix = 0.700 |ddv_scf|^2 = 3.477E-12</div><div>...</div><div>...</div><div> iter # 12 total cpu time : 22432.3 secs <a href="http://av.it">av.it</a>.: 17.7<br></div><div> thresh= 1.628E-09 alpha_mix = 0.700 |ddv_scf|^2 = 1.601E-16</div><div> iter # 13 total cpu time : 24072.0 secs <a href="http://av.it">av.it</a>.: 17.3<br></div><div> thresh= 1.265E-09 alpha_mix = 0.700 |ddv_scf|^2 = <b>1.580E-17</b></div></div><div><br></div><div>even with alpha_mix=0.7 (default value).</div><div><br></div><div>The system is a relaxed CsPbBr3 (I attach the input below).</div><div><br></div><div>Anyone with more experience an idea what to do here?</div><div><br></div><div>Have a good weekend everyone!</div><div><br></div><div>Chris </div><div><br></div><div><div>&control</div><div> calculation = 'scf'</div><div> prefix='cspbbr3',</div><div> pseudo_dir = '../../pseudo',</div><div> outdir='./'</div><div> wf_collect=.true.</div><div> verbosity='high'</div><div> nstep = 500</div><div>/</div><div>&SYSTEM</div><div> ibrav = 0</div><div> A = 8.24400</div><div> nat = 20</div><div> ntyp = 3</div><div> ecutwfc = 100,</div><div> occupations='fixed'</div><div>/</div><div>&ELECTRONS</div><div> conv_thr=1e-17</div><div> diago_thr_init=1e-3</div><div> diagonalization='cg'</div><div>/</div><div>ATOMIC_SPECIES</div><div> Pb 207.20000 Pb_ONCV_PBE-Chris.UPF</div><div> Cs 132.90500 Cs_ONCV_PBE-Chris.UPF </div><div> Br 79.90400 Br_ONCV_PBE-Chris.UPF</div><div><br></div><div>K_POINTS automatic</div><div>9 9 9 0 0 0</div><div>CELL_PARAMETERS (alat= 15.57890224)</div><div> 1.034550924 0.000000000 0.000000000</div><div> 0.000000000 1.442904322 0.000000000</div><div> 0.000000000 0.000000000 1.002723182</div><div><br></div><div>ATOMIC_POSITIONS (crystal)</div><div>Pb 0.000000000 0.500000000 0.000000000</div><div>Pb 0.500000000 0.000000000 0.500000000</div><div>Pb 0.500000000 0.500000000 0.500000000</div><div>Pb 0.000000000 0.000000000 0.000000000</div><div>Cs 0.557073579 0.250000000 0.015983762</div><div>Cs 0.942926421 0.750000000 0.515983762</div><div>Cs 0.442926421 0.750000000 0.984016238</div><div>Cs 0.057073579 0.250000000 0.484016238</div><div>Br 0.293064750 0.462313289 0.204460039</div><div>Br 0.206935250 0.962313289 0.704460039</div><div>Br 0.206935250 0.537686711 0.704460039</div><div>Br 0.706935250 0.962313289 0.795539961</div><div>Br 0.706935250 0.537686711 0.795539961</div><div>Br 0.793064750 0.037686711 0.295539961</div><div>Br 0.793064750 0.462313289 0.295539961</div><div>Br 0.293064750 0.037686711 0.204460039</div><div>Br 0.013732263 0.750000000 0.072407914</div><div>Br 0.486267737 0.250000000 0.572407914</div><div>Br 0.986267737 0.250000000 0.927592086</div><div>Br 0.513732263 0.750000000 0.427592086</div></div><div><br></div><div><div>&inputph</div><div> prefix = 'cspbbr3',</div><div> recover = .false.</div><div> amass(1) = 207.20000</div><div> amass(2) = 132.90500</div><div> amass(3) = 79.90400 </div><div> epsil = .true.,</div><div> fildyn = 'cspbbr3.dyn',</div><div> ldisp = .true.</div><div> nq1=4, nq2=3, nq3=4<br></div><div> fildvscf = 'dvscf'</div><div> tr2_ph = 1.0d-12,</div><div> alpha_mix(1)=0.01</div><div> alpha_mix(2)=0.01</div><div> alpha_mix(3)=0.01</div><div> alpha_mix(4)=0.01</div></div><div>/</div>-- <br><div class="gmail_signature"><div dir="ltr">Postdoctoral Researcher<br>Center for Quantum Nanoscience, Institute for Basic Science<br>Ewha Womans University, Seoul, South Korea<blockquote type="cite" style="font-size:12.8px"><div dir="ltr"><div><div dir="ltr"></div></div></div></blockquote></div></div>
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