<div dir="auto"><div>Hi,</div><div dir="auto"><br></div><div dir="auto">From your input, the main reason your supercell is taking so long is that you have increased the number of atoms to 120, which makes both the electronic SCF and ionic relaxation much heavier than the unit cell. On top of that, you are using an extremely small smearing (`degauss = 0.001`), very tight electronic convergence (`conv_thr = 1e-8`), and a full `vc-relax` (relaxing both ions and cell together). All of these slow things down drastically. To speed up, the practical solution is to first relax only the ions (`calculation='relax'`, `cell_dofree='none'`) until forces are small, and then restart with `vc-relax` for the cell. Increase the smearing to a more reasonable value (`degauss = 0.01–0.02`) and use `smearing='cold'` or `'marzari'`, which will make SCF converge faster. You can also loosen the electronic threshold temporarily (`conv_thr = 1e-6`) during the initial relaxation, and then tighten it for the final run. Additionally, try `diagonalization='cg'` in \&ELECTRONS and adjust `mixing_beta` (0.2–0.3) if convergence is unstable. </div><div dir="auto"><br></div><div dir="auto">So we have to go step by step.</div><div dir="auto">Thank you.</div><div dir="auto"><br><div class="gmail_quote gmail_quote_container" dir="auto"><div dir="ltr" class="gmail_attr">On Wed, 10 Sep, 2025, 5:41 pm Gulshan Kumar, <<a href="mailto:kumargulshan@iitgn.ac.in">kumargulshan@iitgn.ac.in</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="auto"><div>Hi</div><div dir="auto">that’s expected behavior sometimes when you go from a small unit cell to a large doped supercell. A few likely causes: the system size (nat = 120) increases SCF / ionic work a lot, the very small smearing (degauss = 0.001) and very tight conv_thr make each SCF converge slowly, and a full vc-relax (cell + ions) on a large supercell is computationally heavy.</div><div dir="auto"><br></div><div dir="auto">Hope it helps.</div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote" dir="auto"><div dir="ltr" class="gmail_attr">On Wed, 10 Sep, 2025, 5:33 pm Monika Srivastava via users, <<a href="mailto:users@lists.quantum-espresso.org" target="_blank" rel="noreferrer">users@lists.quantum-espresso.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div style="font-family:Helvetica Neue,Helvetica,Arial,sans-serif;font-size:13px"><div></div>
<div><span style="color:rgb(38,40,42)">Please find the attached file I am trying to vc-relax unit cell was optimized in 30hrs but after making supercell with strontium doping it is keep on going more than 120 hrs and still running without giving any error</span></div></div><div id="m_-837228874589519380m_-2753284502650577590ydp7088de55yahoo_quoted_8284649992"><div style="font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;font-size:13px;color:#26282a"><div><div id="m_-837228874589519380m_-2753284502650577590ydp7088de55yiv0297553705"><div style="font-family:Helvetica Neue,Helvetica,Arial,sans-serif;font-size:13px"><div dir="ltr"><br></div><div dir="ltr"><div><div>&CONTROL</div><div> calculation = "vc-relax"</div><div> max_seconds = 84600</div><div> prefix ="lsmo"</div><div> outdir ="./outdir_lsmo"</div><div> restart_mode = "from_scratch"</div><div> pseudo_dir = "/net/pr2/projects/plgrid/plggkowalskigroup/Sandra_work/LSMO/pseudo"</div><div> etot_conv_thr = 1e-05</div><div> forc_conv_thr = 1e-04</div><div> disk_io = "high"</div><div>/</div><div><br></div><div>&SYSTEM</div><div> ibrav = 0</div><div> nat = 120</div><div> ntyp = 4</div><div> nspin = 2</div><div> ecutwfc = 45</div><div> ecutrho = 180 </div><div> occupations = "smearing"</div><div> smearing = "gaussian"</div><div> degauss = 0.001</div><div> starting_magnetization(1) = 0.00000e+00</div><div> starting_magnetization(2) = 2.00000e-01</div><div> starting_magnetization(3) = 0.00000e-01</div><div>/</div><div><br></div><div>&ELECTRONS</div><div> conv_thr = 1.00000e-8</div><div> electron_maxstep = 500</div><div> mixing_beta = 2.5000000e-01</div><div> startingpot = "atomic"</div><div> startingwfc = "atomic+random"</div><div> diago_david_ndim = 4</div><div>/ </div><div><br></div><div>&IONS</div><div> ion_dynamics = "bfgs"</div><div>/</div><div><br></div><div>&CELL</div><div> cell_dynamics = "bfgs"</div><div> cell_dofree = "all"</div><div>/</div><div><br></div><div>ATOMIC_SPECIES</div><div>Mn 54.93805 mn_pbe_v1.5.uspp.F.UPF</div><div>O 15.99940 O.pbe-n-kjpaw_psl.0.1.UPF</div><div>La 138.90550 La.paw.z_11.atompaw.wentzcovitch.v1.2.upf</div><div>Sr 87.62 Sr_pbe_v1.uspp.F.UPF</div><div><br></div><div>CELL_PARAMETERS (angstrom)</div><div> 11.2969865799 0.0000000000 0.0000000000</div><div> -5.6484932899 9.7834773644 0.0000000000</div><div> 0.0000000000 0.0000000000 13.5085849762</div><div><br></div><div>ATOMIC_POSITIONS (crystal)</div><div> Mn 0.0000000000 0.0000000000 0.0000000000</div><div> Mn 0.0000000000 0.5000000000 0.0000000000</div><div> Mn 0.5000000000 0.0000000000 0.0000000000</div><div> Mn 0.5000000000 0.5000000000 0.0000000000</div><div> O 0.3333294689 0.8804080486 0.0833345577</div><div> O 0.1195919811 0.4529214501 0.0833345577</div><div> O 0.6195919514 0.4529214501 0.0833345577</div><div> O 0.8333294392 0.8804080486 0.0833345577</div><div> O 0.1195919439 0.9529213309 0.0833345577</div><div> O 0.3333294690 0.3804080188 0.0833345577</div><div> O 0.5470785498 0.6666705608 0.0833345577</div><div> O 0.0470785908 0.6666705608 0.0833345577</div><div> O 0.8333294391 0.3804080188 0.0833345577</div><div> O 0.0470785759 0.1666705459 0.0833345577</div><div> O 0.5470785499 0.1666705459 0.0833345577</div><div> O 0.6195919514 0.9529213309 0.0833345577</div><div> Sr 0.8333333731 0.6666666865 0.0833349600</div><div> Sr 0.3333333432 0.1666666716 0.0833349600</div><div> La 0.8333333731 0.1666666716 0.0833349600</div><div> La 0.3333333432 0.6666666865 0.0833349600</div><div> Mn 0.6666666865 0.3333333433 0.1666651666</div><div> Mn 0.6666666865 0.8333333134 0.1666651666</div><div> Mn 0.1666666418 0.8333333134 0.1666651666</div><div> Mn 0.1666666716 0.3333333433 0.1666651666</div><div> O 0.0000045120 0.2862591147 0.2499982566</div><div> O 0.7862546444 0.9999954701 0.2499982566</div><div> O 0.5000045299 0.2862591147 0.2499982566</div><div> O 0.7137408852 0.7137453557 0.2499982566</div><div> O 0.2137408704 0.7137453557 0.2499982566</div><div> O 0.0000045332 0.7862591148 0.2499982566</div><div> O 0.5000045300 0.7862591148 0.2499982566</div><div> O 0.7862546444 0.4999954998 0.2499982566</div><div> O 0.2137408704 0.2137453854 0.2499982566</div><div> O 0.2862546146 0.4999954998 0.2499982566</div><div> O 0.2862546146 0.9999954701 0.2499982566</div><div> O 0.7137408853 0.2137453854 0.2499982566</div><div> Sr 0.5000000000 0.5000000000 0.2500008941</div><div> La 0.5000000000 0.0000000000 0.2500008941</div><div> La 0.0000000000 0.0000000000 0.2500008941</div><div> La 0.0000000000 0.5000000000 0.2500008941</div><div> Mn 0.3333333432 0.1666666716 0.3333334625</div><div> Mn 0.8333333731 0.1666666716 0.3333334625</div><div> Mn 0.8333333731 0.6666666865 0.3333334625</div><div> Mn 0.3333333432 0.6666666865 0.3333334625</div><div> La 0.1666666716 0.3333333433 0.4166661203</div><div> Sr 0.6666666865 0.8333333134 0.4166661203</div><div> La 0.1666666418 0.8333333134 0.4166661203</div><div> La 0.6666666865 0.3333333433 0.4166661203</div><div> O 0.4529260695 0.6195876598 0.4166683852</div><div> O 0.9529260397 0.6195876598 0.4166683852</div><div> O 0.4529260695 0.1195876374 0.4166683852</div><div> O 0.1666615754 0.5470739603 0.4166683852</div><div> O 0.6666615605 0.5470739603 0.4166683852</div><div> O 0.9529260397 0.1195876374 0.4166683852</div><div> O 0.3804123402 0.8333383798 0.4166683852</div><div> O 0.1666615605 0.0470739342 0.4166683852</div><div> O 0.6666615605 0.0470739342 0.4166683852</div><div> O 0.8804123402 0.8333383798 0.4166683852</div><div> O 0.8804123402 0.3333384394 0.4166683852</div><div> O 0.3804123700 0.3333384394 0.4166683852</div><div> Mn 0.0000000000 0.5000000000 0.5000000000</div><div> Mn 0.5000000000 0.5000000000 0.5000000000</div><div> Mn 0.0000000000 0.0000000000 0.5000000000</div><div> Mn 0.5000000000 0.0000000000 0.5000000000</div><div> O 0.8333384394 0.9529260397 0.5833316446</div><div> O 0.3333384394 0.9529260397 0.5833316446</div><div> O 0.5470739603 0.8804123401 0.5833316446</div><div> O 0.6195876598 0.6666615605 0.5833316446</div><div> O 0.1195876300 0.6666615605 0.5833316446</div><div> O 0.0470739007 0.8804123401 0.5833316446</div><div> O 0.8333384395 0.4529260695 0.5833316446</div><div> O 0.3333384395 0.4529260695 0.5833316446</div><div> O 0.6195876598 0.1666615605 0.5833316446</div><div> O 0.0470739268 0.3804123700 0.5833316446</div><div> O 0.5470739604 0.3804123700 0.5833316446</div><div> O 0.1195876300 0.1666615605 0.5833316446</div><div> La 0.3333333432 0.1666666716 0.5833338499</div><div> La 0.8333333731 0.1666666716 0.5833338499</div><div> Sr 0.8333333731 0.6666666865 0.5833338499</div><div> La 0.3333333432 0.6666666865 0.5833338499</div><div> Mn 0.6666666865 0.3333333433 0.6666665674</div><div> Mn 0.1666666418 0.8333333134 0.6666665674</div><div> Mn 0.1666666716 0.3333333433 0.6666665674</div><div> Mn 0.6666666865 0.8333333134 0.6666665674</div><div> La 0.5000000000 0.0000000000 0.7499991060</div><div> La 0.0000000000 0.5000000000 0.7499991060</div><div> Sr 0.5000000000 0.5000000000 0.7499991060</div><div> La 0.0000000000 0.0000000000 0.7499991060</div><div> O 0.2137453854 0.0000045078 0.7500017285</div><div> O 0.2862591148 0.7862546444 0.7500017285</div><div> O 0.7862591148 0.7862546444 0.7500017285</div><div> O 0.7137454152 0.0000045078 0.7500017285</div><div> O 0.7862591147 0.2862546146 0.7500017285</div><div> O 0.9999954701 0.7137408853 0.7500017285</div><div> O 0.2862591147 0.2862546146 0.7500017285</div><div> O 0.9999954701 0.2137408853 0.7500017285</div><div> O 0.4999954701 0.2137408853 0.7500017285</div><div> O 0.4999954700 0.7137408853 0.7500017285</div><div> O 0.7137454152 0.5000045300 0.7500017285</div><div> O 0.2137454003 0.5000045300 0.7500017285</div><div> Mn 0.3333333432 0.6666666865 0.8333347440</div><div> Mn 0.8333333731 0.6666666865 0.8333347440</div><div> Mn 0.3333333432 0.1666666716 0.8333347440</div><div> Mn 0.8333333731 0.1666666716 0.8333347440</div><div> La 0.1666666716 0.3333333433 0.9166650772</div><div> La 0.6666666865 0.3333333433 0.9166650772</div><div> Sr 0.6666666865 0.8333333134 0.9166650772</div><div> La 0.1666666418 0.8333333134 0.9166650772</div><div> O 0.1666705460 0.1195919737 0.9166654348</div><div> O 0.6666705609 0.1195919737 0.9166654348</div><div> O 0.8804080486 0.5470785498 0.9166654348</div><div> O 0.1666705459 0.6195919513 0.9166654348</div><div> O 0.9529213905 0.8333294391 0.9166654348</div><div> O 0.4529214203 0.3333294690 0.9166654348</div><div> O 0.9529213906 0.3333294690 0.9166654348</div><div> O 0.4529214203 0.8333294391 0.9166654348</div><div> O 0.3804080188 0.0470785759 0.9166654348</div><div> O 0.8804080486 0.0470785759 0.9166654348</div><div> O 0.3804080189 0.5470785498 0.9166654348</div><div> O 0.6666705608 0.6195919513 0.9166654348</div><div><br></div><div>K_POINTS {automatic}</div><div> 2 2 1 0 0 0</div><div><br></div><div>HUBBARD (ortho-atomic)</div><div>U Mn-3d 4.0</div><div><br></div></div><br></div></div></div></div>
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