<div dir="ltr"><div dir="ltr">
<p>Dear all,</p>
<p>Thank you very much for your helpful insights and suggestions.</p>
<p>Based on your comments, I now realize that the slab I initially constructed was incorrectly terminated—more representative of a (100) surface rather than Au(111). Additionally, the excessive lateral cell dimensions likely contributed to nonphysical behavior, effectively causing the slab to behave like a cluster during optimization.</p>
<p>I have now reconstructed the slab with correct Au(111) termination, appropriate lattice constants, and reduced lateral vacuum. I also applied constraints to fix the bottom two layers (32 atoms) to stabilize the slab. However, despite these corrections, I still observe significant restructuring during the geometry optimization of the Au slab <em>alone</em>, even without the C₆₀ molecule.</p>
<p>To facilitate further advice, I will attach the updated input file and trajectory from this latest attempt.</p>
<p>Thank you again for your support.</p>
<p>Best regards,<br>
Hamid Zabihi</p>
<br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Jul 9, 2025 at 1:27 PM Daniele Passerone <<a href="mailto:dpasserone@gmail.com" target="_blank">dpasserone@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi, there are at least a couple of problems in your input files. <div><br></div><div>The first one is the one mentioned by marcella: The termination is a 100, that is going to reconstruct to increase the lateral density (to a triangular close packed layer). </div><div>The other one is that your cell has a lateral dimension <br><br> &CELL<br> ABC 22.9836444855 40.0 22.9836444855 <br> PERIODIC XZ<br> &END CELL</div><div><br></div><div>And since the default (see manual<br><a href="https://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/SUBSYS/CELL.html" target="_blank">https://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/SUBSYS/CELL.html</a></div><div><br>) is Angstrom, your system has a lot of empty space laterally, and this is seen in the optimization trajectory where the not-fixed atoms are behaving like a cluster and not as a slab.</div><div><br></div><div>HTH<br><br>Daniele</div><div><br><br></div><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Wednesday, July 9, 2025 at 11:50:20 AM UTC+2 Marcella Iannuzzi wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi Hamid, <div><br></div><div>Are you sure that the Au coordinates correspond to a Au(111) slab?</div><div>I just had a quick look, but the staking looks weird.</div><div><br></div><div>Regards</div><div>Marcella<br><br></div><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Wednesday, July 9, 2025 at 6:47:51 AM UTC+2 <a rel="nofollow">hamidzabihi...@gmail.com</a> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<p>Dear CP2K community,</p>
<p>I am performing a geometry optimization of a <b>C₆₀ molecule adsorbed on an Au(111) slab</b>, using <b>PBE+D3</b> and <b>DZVP-MOLOPT-SR-GTH</b> basis sets.</p>
<p>The initial configuration had C₆₀ placed ~3 Å above the gold surface. However, after optimization, I noticed that <b>several top-layer Au atoms were pulled significantly upward</b>—toward the C₆₀. This distortion seems nonphysical and may indicate issues with my setup or parameters.</p>
<p>I would be grateful for any advice on:</p>
<ul><li>
<p>Best practices for modeling <b>molecule-surface interactions</b> in CP2K</p>
</li><li>
<p>Ensuring <b>slab stability</b> and correct <b>adsorption behavior</b></p>
</li><li>
<p>Whether this is a known issue with this CP2K version or functional</p>
</li></ul>
<p><b>System details:</b></p>
<ul><li>
<p>CP2K version: 8.0 (development)</p>
</li><li>
<p>Functional: PBE with D3 dispersion correction</p>
</li><li>
<p>Basis sets: DZVP-MOLOPT-SR-GTH</p>
</li><li>
<p>Slab: 4-layer Au(111), ~15 Å vacuum in y-direction, bottom layers unconstrained</p>
</li></ul>
<p>I’ve attached the following files:</p>
<ul><li>
<p><span>cp2k_c60_au_geoopt.inp</span>: Input file</p>
</li><li>
<p><span>out-C60_Au_GEO_OPT.log</span>: Optimization output</p>
</li><li>
<p><span>C60_Au_opt-trajectory.xyz-pos-1</span>: Final trajectory</p>
</li></ul>
<p>Thank you in advance for your help!</p>
<p>Best regards,<br>
<b>Hamid Zabihi</b></p>
<br></blockquote></div></blockquote></div>
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