<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>Il giorno 24/feb/2011, alle ore 10.10, <a href="mailto:giuseppe.mattioli@mlib.ism.cnr.it">giuseppe.mattioli@mlib.ism.cnr.it</a> ha scritto:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div><br><br>Dear Christopher<br>You should try to reduce conv_thr in &ELECTRONS, in order to have a<br>more accurate calculation of forces and stress. Try, for instance,<br>with conv_thr = 1.0d-9 (and with a lower mixing_beta, 0.2~0.3 or so,<br>if the electronic calculation does not converge).<br></div></blockquote><div><br></div><div>Alternatively you can use upscale=1.D3 in &IONS (the default should be 1.D1, if I remember well).</div><div><br></div><br><blockquote type="cite"><div>HTH<br><br>Giuseppe<br><br>Quoting Christopher O'Brien <<a href="mailto:cjobrien@ncsu.edu">cjobrien@ncsu.edu</a>>:<br><br><blockquote type="cite">Below this is a super-cell of an interface of Cu2O and Ti. The <br></blockquote><blockquote type="cite">problem is simply that the forc_conv_thr is not met within 100 <br></blockquote><blockquote type="cite">iterations. etot_conv_thr is almost always met first (even <br></blockquote><blockquote type="cite">decreasing etot_conv_thr to 1.0d-6). Typically, the force in this <br></blockquote><blockquote type="cite">system decreases to ~0.01 Ry/B with a delta F on the same order of <br></blockquote><blockquote type="cite">magnitude but fluctuates about this value. This means that I <br></blockquote><blockquote type="cite">continually get the warning telling me to reduce the convergence <br></blockquote><blockquote type="cite">threshold. Ideally I would like obtain a maximum force of ~1D-4.<br></blockquote></div></blockquote><div><br></div><div>This threshold looks very tight to me. The default of 1.D-3 is often sufficient. If you really need such a good accuracy, you might also need to increase the cutoffs to get more precise forces. All the elements in your compound are pretty unfriendly to planewaves, even when using ultrasoft pseudos (Cu and Ti have 3d electrons in valence, O has 2p).</div><div>I suggest you to perform a test on the force convergence w.r.t. ecutwfc.</div><div><br></div><div>HTH</div><div><br></div><div>GS</div><div><br></div><div><br></div><blockquote type="cite"><div><blockquote type="cite">Does anyone have any suggestions? I am at a loss.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Thanks in advance,<br></blockquote><blockquote type="cite">Chris O'Brien<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">title = 'Cu2O-Ti-case2' ,<br></blockquote><blockquote type="cite">calculation = 'vc-relax' ,<br></blockquote><blockquote type="cite">restart_mode = 'from_scratch' ,<br></blockquote><blockquote type="cite">wf_collect = .false. ,<br></blockquote><blockquote type="cite">outdir = './',<br></blockquote><blockquote type="cite">wfcdir = './',<br></blockquote><blockquote type="cite">pseudo_dir = '/share2/cjobrien/pseudo/',<br></blockquote><blockquote type="cite">prefix = 'Cu2OTi',<br></blockquote><blockquote type="cite">disk_io = 'low',<br></blockquote><blockquote type="cite">verbosity = 'minimal',<br></blockquote><blockquote type="cite">tstress = .true.,<br></blockquote><blockquote type="cite">tprnfor = .true.,<br></blockquote><blockquote type="cite">forc_conv_thr = 1.0d-4,<br></blockquote><blockquote type="cite">etot_conv_thr = 1.0d-5,<br></blockquote><blockquote type="cite">/<br></blockquote><blockquote type="cite">&SYSTEM<br></blockquote><blockquote type="cite">ibrav = 0,<br></blockquote><blockquote type="cite">celldm(1) = 8.1878,<br></blockquote><blockquote type="cite">nat = 14,<br></blockquote><blockquote type="cite">ntyp = 3,<br></blockquote><blockquote type="cite">ecutwfc = 30.0 ,<br></blockquote><blockquote type="cite">ecutrho = 300.0 ,<br></blockquote><blockquote type="cite">occupations = 'smearing' ,<br></blockquote><blockquote type="cite">smearing = 'mv' ,<br></blockquote><blockquote type="cite">degauss = 0.01 ,<br></blockquote><blockquote type="cite">/<br></blockquote><blockquote type="cite">&ELECTRONS<br></blockquote><blockquote type="cite">conv_thr = 1.0d-6 ,<br></blockquote><blockquote type="cite">mixing_beta = 0.7 ,<br></blockquote><blockquote type="cite">/<br></blockquote><blockquote type="cite">&IONS<br></blockquote><blockquote type="cite">ion_dynamics = 'bfgs',<br></blockquote><blockquote type="cite">/<br></blockquote><blockquote type="cite">&CELL<br></blockquote><blockquote type="cite">cell_dynamics = 'bfgs',<br></blockquote><blockquote type="cite">press = 0.0,<br></blockquote><blockquote type="cite">cell_dofree = 'xyz',<br></blockquote><blockquote type="cite">/<br></blockquote><blockquote type="cite">CELL_PARAMETERS<br></blockquote><blockquote type="cite">0.929429709 0.0 0.0<br></blockquote><blockquote type="cite">0.0 0.929429709 0.0<br></blockquote><blockquote type="cite">0.0 0.0 2.924945006<br></blockquote><blockquote type="cite">ATOMIC_SPECIES<br></blockquote><blockquote type="cite">Cu 58.70000 Cu.pw91-n-van_ak.UPF<br></blockquote><blockquote type="cite">Ti 47.88000 Ti.pw91-nsp-van.UPF<br></blockquote><blockquote type="cite">O 16.00000 O.pw91-van_ak.UPF<br></blockquote><blockquote type="cite">ATOMIC_POSITIONS alat<br></blockquote><blockquote type="cite">Cu 0 0 0<br></blockquote><blockquote type="cite">Cu 0.504691013 0.504691013 0<br></blockquote><blockquote type="cite">Cu 0.484702934 0.019988079 0.553031754<br></blockquote><blockquote type="cite">Cu 0.019988079 0.484702934 0.553031754<br></blockquote><blockquote type="cite">Cu 0.039976158 0.039976158 1.106063508<br></blockquote><blockquote type="cite">Cu 0.464714854 0.464714854 1.106063508<br></blockquote><blockquote type="cite">O 0.252345506 0.252345506 0.285738983<br></blockquote><blockquote type="cite">O 0.024221288 0.024221288 1.544049139<br></blockquote><blockquote type="cite">Ti 0.480469725 0.024221288 1.544049139<br></blockquote><blockquote type="cite">Ti 0.024221288 0.480469725 1.544049139<br></blockquote><blockquote type="cite">Ti 0.484702934 0.484702934 2.015504257<br></blockquote><blockquote type="cite">Ti 0.019988079 0.019988079 2.015504257<br></blockquote><blockquote type="cite">Ti 0.01575487 0.488936142 2.486959376<br></blockquote><blockquote type="cite">Ti 0.488936142 0.01575487 2.486959376<br></blockquote><blockquote type="cite">K_POINTS automatic<br></blockquote><blockquote type="cite">8 8 4 0 0 0<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">===================================================================<br></blockquote><blockquote type="cite">Christopher J. O'Brien<br></blockquote><blockquote type="cite"><a href="mailto:cjobrien@ncsu.edu">cjobrien@ncsu.edu</a><br></blockquote><blockquote type="cite"><a href="https://sites.google.com/a/ncsu.edu/cjobrien/">https://sites.google.com/a/ncsu.edu/cjobrien/</a><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Ph.D. Candidate<br></blockquote><blockquote type="cite">Computational Materials Group<br></blockquote><blockquote type="cite">Department of Materials Science & Engineering<br></blockquote><blockquote type="cite">North Carolina State University<br></blockquote><blockquote type="cite">__________________________________________________________________<br></blockquote><blockquote type="cite">Please send all documents in PDF.<br></blockquote><blockquote type="cite">For Word documents: Please use the 'Save as PDF' option before sending.<br></blockquote><blockquote type="cite">===================================================================<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">_______________________________________________<br></blockquote><blockquote type="cite">Pw_forum mailing list<br></blockquote><blockquote type="cite"><a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br></blockquote><blockquote type="cite"><a href="http://www.democritos.it/mailman/listinfo/pw_forum">http://www.democritos.it/mailman/listinfo/pw_forum</a><br></blockquote><blockquote type="cite"><br></blockquote><br>Giuseppe Mattioli<br>ISM-CNR, Italy<br><br><br><br>_______________________________________________<br>Pw_forum mailing list<br><a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>http://www.democritos.it/mailman/listinfo/pw_forum<br></div></blockquote></div><br><div>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div><span class="Apple-style-span" style="color: rgb(126, 126, 126); font-size: 16px; font-style: italic; "><br class="Apple-interchange-newline">§ Gabriele Sclauzero, EPFL SB ITP CSEA</span></div><div><font class="Apple-style-span" color="#7E7E7E"><i> PH H2 462, Station 3, CH-1015 Lausanne</i></font></div></span>
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