<div>Hi Manuel,</div><div><br></div><div>According to the manuel the wavelet solver supports
<em>"slab-boundary conditions (but only PERIODIC XZ)." </em>You are correct to change the k-point grid accordingly.<br><em></em>
</div><div><br></div><div>To avoid the warning you mentioned need to increase the cell length in the y-direction.<br></div><div><br></div><div>To reduce the number of scf iterations you can optimize the &MIXING section, in particular
<a href="https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/SCF/MIXING.html#NBUFFER">NBUFFER</a>
and
<a href="https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/SCF/MIXING.html#ALPHA">ALPHA</a>. If you don't expect the multiplicity to change during MD you can disable RELAX_MULTIPLICITY to further improve scf convergence. And lastly you can tune the
<a href="https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/QS.html#EXTRAPOLATION">EXTRAPOLATION.</a></div><div><br></div><div>Cheers,</div><div>Fabian<br>
</div><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Tuesday, 19 January 2021 at 14:14:42 UTC+1 Manuel Corral wrote:<br/></div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Dear Fabian,<div><br></div><div>Thank you very much for the commented file. It works, which it is already a huge improvement, though it may take about 75 electronic iterations for each ionic step, which may render a MD calculation too expensive. I wonder if there is anything that could be done to speed it up.<br><br></div><div>By the way, why do you need to rotate the cell for the Wavelet Poisson solver ? Based on this rotation, I would have thought of changing the Monkhorst Pack set of k-points from 7x7x1 to 7x1x7, which you didn't and, when I tried it, it did not work properly:</div><div><span style="font-size:14px"><br></span></div><div><span style="font-size:14px"> *** WARNING in pw/ps_wavelet_methods.F:236 :: Density non-zero on the ***</span></div><div><span style="font-size:14px"> *** edges of the unit cell: wrong results in WAVELET solver</span>.</div><div><br></div><div>Thanks again.</div><div><br></div><div>Regards,</div><div>Manuel</div><div><br></div><div class="gmail_quote"><div dir="auto" class="gmail_attr">Le lundi 18 janvier 2021 à 18:03:26 UTC+1, <a href data-email-masked rel="nofollow">fa...@gmail.com</a> a écrit :<br></div><blockquote class="gmail_quote" style="margin:0 0 0 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>Dear Manuel,</div><div><br></div><div>I changed a couple of things in the input and it's converging now (attached below). The changes include:<br></div><div> To use the WAVELET poisson solver I rotated the slab such that B is the surface vector. <br></div><div>I also decreased RELAX_MULTIPLICITY because large values hinder scf onvergence. Maybe you need to test various initial guesses (see here: <a href="https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/SUBSYS/KIND/BS.html" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en-GB&q=https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/SUBSYS/KIND/BS.html&source=gmail&ust=1611151248453000&usg=AFQjCNHqTw-uPNCIe83bDBKR6HfcG6vxmg">https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/SUBSYS/KIND/BS.html</a>) to find the minimal energy configuration.</div><div>I increased the ELECTRONIC_TEMPERATURE in the &SEMEAR section. 300 K corresponds to just 0.02 eV in VASP which is very little.</div><div><br></div><div>Cheers,</div><div>Fabian<br></div><br><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Monday, 18 January 2021 at 14:53:36 UTC+1 Manuel Corral wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Dear Colleagues,<div><br></div><div>I have been trying to run a geometry optimization for with a Co(111) 4-layer slab model without success. </div><div><br></div><div>I set up my initial input file according my previous experience with another software (VASP) and then changed different calculation settings: number of additional MOS (10, 30, 100), electronic temperature of the smearing (300 K, 500 K), decreasing the cell in the vacuum direction, changing the number of kpoints (gamma point with an increased cell), the Poisson solver (analytical vs non analytical), the diagonalization algorithm, settings in the mixing algorithm ... nothing worked. The SCF cycle never converges.</div><div><br></div><div>I would very much appreciate if you could give some advice or feedback on my input files (enclosed).</div><div><br></div><div>Thank you in advance for your help.</div><div><br></div><div>Kind regards,</div><div>Manuel Corral</div><div><br></div></blockquote></div></blockquote></div></blockquote></div>