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<p class="MsoNormal"><span lang="EN-GB" style="mso-fareast-language:EN-US">Hi Rui Zou<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="mso-fareast-language:EN-US">There are two issues which might hamper the convergence process of your cell_opt run:<o:p></o:p></span></p>
<ol style="margin-top:0cm" start="1" type="1">
<li class="MsoListParagraph" style="margin-left:0cm;mso-list:l0 level1 lfo1"><span lang="EN-GB" style="mso-fareast-language:EN-US">The SCF convergence threshold value is with 5.0E-6 quite large which will cause a low accuracy of the calculated forces. Noisy
 forces will in turn “confuse” the optimizer.<o:p></o:p></span></li><li class="MsoListParagraph" style="margin-left:0cm;mso-list:l0 level1 lfo1"><span lang="EN-GB" style="mso-fareast-language:EN-US">The applied constraints KEEP_ANGLES and KEEP_SYMMETRY might prevent the optimiser from finding an energetically lower lying structure
 with less symmetry indicated by residual forces.<o:p></o:p></span></li></ol>
<p class="MsoNormal"><span lang="EN-GB" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="mso-fareast-language:EN-US">HTH<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="mso-fareast-language:EN-US">Matthias<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:35.4pt"><b>Von:</b> cp...@googlegroups.com <...@googlegroups.com>
<b>Im Auftrag von </b>rui zou<br>
<b>Gesendet:</b> Freitag, 25. Dezember 2020 05:41<br>
<b>An:</b> cp2k <...@googlegroups.com><br>
<b>Betreff:</b> [CP2K:14431] Cell_OPT convergence is too slow<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-left:35.4pt">Hi everyone!<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">I am a new user of CP2K. I want to use CP2K to optimize the cell. However, the convergence of this process is too slow. Can you help me check if there is a problem with my input file? Thank  you so much!<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">Best regards,<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">Rui Zou<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">-- <br>
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