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Dear Fabian and Lenard,</div>
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<span id="" title="" class="">Thank you for your suggestions! I'll try that to get a more reasonable structure first.</span></div>
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<span title="" class="">Best regards,</span></div>
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<span title="" class="">Xiao Wang</span></div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> cp...@googlegroups.com <...@googlegroups.com> on behalf of fa...@gmail.com <fabi...@gmail.com><br>
<b>Sent:</b> Monday, March 1, 2021 6:59 PM<br>
<b>To:</b> cp2k <...@googlegroups.com><br>
<b>Subject:</b> [CP2K:14845] Re: Energy Fluctuations in Geometry Optimization</font>
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<div>Hi Xiao,</div>
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<div>As Lenard pointed out your SCF does not converge, consequently the forces are not converged and BFGS cannot optimize the structure.</div>
<div>You should adjust a few parameters:<br>
MAX_SCF 200 ! change if needed to make sure SCF is really converged<br>
ELECTRONIC_TEMPERATURE 2000 ! large smearing helps convergence. If needed you can reduce this once the optimization is converged and restart</div>
<div>ALPHA 0.01 ! you can play with this but it probably needs to be << 0.1</div>
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<div>To speed up the first few steps of geometry optimization you could consider reducing the k-point grid to something like</div>
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<div> SCHEME MONKHORST-PACK 2 3 1<br>
!FULL_GRID .TRUE.</div>
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<div>Once the the geometry is more reasonable you can switch back the the more accurate k-point sampling.<br>
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<div>Cheers,</div>
<div>Fabian<br>
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<div dir="auto" class="x_gmail_attr">On Sunday, 28 February 2021 at 20:36:45 UTC+1 ASSIDUO Network wrote:<br>
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If I'm not mistaken, I think your structure is too far away from the optimized geometry. Your best bet would probably be to get the best structure possible before starting the geometry optimization.<br>
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This is true because I see the following in your output file:<br>
At the 50th cycle your convergence criterion is around 0.9, nowhere near 1.0E-07, and you also get a message of "SCF run NOT converged".<br>
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I don't really see any issues with the flags you chose, so I think your issue is probably with the structure. The same thing happened to me the other day.
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<div dir="auto" class="x_gmail_attr">On Saturday, February 27, 2021 at 7:15:49 PM UTC+2
<a href="" rel="nofollow">ti...@hotmail.com</a> wrote:<br>
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Dear CP2K Users,</div>
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I'm trying to run a geometry optimization for CoF2 (110) slabs, but the energy does not seem to decrease. Instead, it fluctuates a lot and sometimes increases significantly. I already used BFGS as the optimizer, and the eps_scf was set to 10^(-7). I'm wondering
if anyone knows how to deal with such a problem. My input file, the generated xyz file, and the output file are attached below.</div>
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Thanks in advance!</div>
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Best regards,</div>
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Xiao</div>
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