<div dir="ltr"><div>Dear Katharina,</div><div><br></div><div>I just ran a quick test for the EXT_POTENTIAL keyword. System: small organic molecule on top of gold (charge-neutral periodic system using standard periodic solver). The keyword still seems to work as intended: when preparing a plane-averaged plot in z-direction, the potential is not zero in the region of the metal, but the value defined by EXT_POTENTIAL. I can send you my example input files; feel free to contact me directly (<a href="mailto:doroth...@aalto.fi">doroth...@aalto.fi</a>).</div><div><br></div><div>Best regards,</div><div>Dorothea<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Am Fr., 26. Juni 2020 um 17:00 Uhr schrieb Dorothea Golze <<a href="mailto:doroth...@googlemail.com">doroth...@googlemail.com</a>>:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Dear Katharina,</div><div><br></div><div>in short, it is very likely no bug; I think the basic problem is that you try to run a periodic DFT calculation for a charged system.<br> The constant potential condition is a hard constraint for the average. I tested with the standard periodic solver (for periodic systems) and the MT solver (for a cluster-type of approach). <br></div><div>I don't have it in the paper, but in my thesis, I have an example, where I placed an ion above a slab (Figure 3.7 page 31, <a href="https://www.zora.uzh.ch/id/eprint/116638/" rel="noreferrer noopener" target="_blank">https://www.zora.uzh.ch/id/eprint/116638/</a>)</div><div> For the MT solver, I have the suspicion you are not applying this solver correctly, which can lead to technical artifacts. You need lots of vacuum around your system since you also specified a periodic cell, this seems not to be the case. I suggest to test the MT solver for a single molecule (DFT only) first to get a feeling how much vacuum you need, i.e., to converge out the cell size and how this solver behaves.<br></div><div><br></div><div>Best regards,</div><div>Dorothea<br></div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Am Fr., 26. Juni 2020 um 16:32 Uhr schrieb Katharina Doblhoff-Dier <<a href="mailto:k.doblh...@lic.leidenuniv.nl" target="_blank">k.doblh...@lic.leidenuniv.nl</a>>:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Dear Dorothea,</div><div>To break a complex problem down: Should I consider it a bug, that I get non-constant potentials in the plot of the hartree energies, when using MT or implicit BCs and that potential in the metal does not match EXT_POTENTIAL? (see plot below - also posted in the original question) Or is there a good reason for this behavior?</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div style="margin-left:40px">red: IMPLICIT poissn solver with Neumann BC at z=0 and z=60 and homogeneous Dirichlet BC at z=30</div><div style="margin-left:40px">green: MT (Martyna-Tuckerman) poisson solver (shifted by 0.4V)</div><div style="margin-left:40px">blue: normal Ewald summation (shifted by 0.4V)<br></div><div><br></div><p style="text-align:center;clear:both"><img style="margin-left: 1em; margin-right: 1em;" src="https://groups.google.com/group/cp2k/attach/13361e99fe472/tmp3.png?part=0.3&view=1&authuser=0" alt="tmp3.png" width="400" height="337"></p><p style="text-align:center;clear:both"><br></p><br></div></blockquote></div></blockquote><div>Thank you for your help!</div><div>Best regards,</div><div>Katharina</div><div><br></div></div> <p></p> -- <br> You received this message because you are subscribed to the Google Groups "cp2k" group.<br> To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp...@googlegroups.com" target="_blank">cp...@googlegroups.com</a>.<br> To view this discussion on the web visit <a href="https://groups.google.com/d/msgid/cp2k/168440d5-5b57-4075-900e-876a99f8e437o%40googlegroups.com?utm_medium=email&utm_source=footer" target="_blank">https://groups.google.com/d/msgid/cp2k/168440d5-5b57-4075-900e-876a99f8e437o%40googlegroups.com</a>.<br> </blockquote></div> </blockquote></div>