Dear Matthias,<div><br></div><div>I have tested these two methods. </div><div>For the first &DIAGONALIZATION plus &KPOINTS method, I find it somewhat strange that even if I switch on &OUTER_SCF, SCF will still exist with non-converged warning, and by now I have no idea about it. So I turn to the second.</div><div>For the second that to set MULTIPLE_UNIT_CELL both in &CELL and &TOPOLOGY, it works quite well and I find for accuracy of structure prediction (bond length, cell parameters, etc.), it is even not necessary to use DFT+U to tune electron delocalization property of Ti (both anatase and rutile TiO2), although for band structure calculation, DFT+U is usually critical.<br>I share information above here and hope it will be useful for other users.</div><div><br></div><div>Thank you again.</div><div>Yike</div><div class="gmail_quote"><div dir="auto" class="gmail_attr">在2021年5月16日星期日 UTC+2 下午6:46:31<Matthias Krack> 写道：<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 lang="EN-US" link="blue" vlink="purple"> <div> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Hi Yike<u></u><u></u></span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Your simulation cell is small and you use no k point sampling. Either you use k point sampling or you enlarge your simulation cell to at least a cell edge length of 12 A in each direction. I suggest the latter option for CP2K. Furthermore, you could reduce EPS_DEFAULT to 1.0E-12 and increase REL_CUTOFF to 60.<u></u><u></u></span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">HTH<u></u><u></u></span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Matthias<u></u><u></u></span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p> <div style="border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt"></div></div></div><div lang="EN-US" link="blue" vlink="purple"><div><div style="border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt"> <div> <div style="border:none;border-top:solid #e1e1e1 1.0pt;padding:3.0pt 0cm 0cm 0cm"> <p class="MsoNormal"><b><span lang="DE" style="font-size:11.0pt;font-family:"Calibri",sans-serif">Von:</span></b><span lang="DE" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <a href data-email-masked rel="nofollow">c...@googlegroups.com</a> <<a href data-email-masked rel="nofollow">c...@googlegroups.com</a>> <b>Im Auftrag von </b>Yike Huang<br> <b>Gesendet:</b> Sonntag, 16. Mai 2021 18:23<br> <b>An:</b> cp2k <<a href data-email-masked rel="nofollow">c...@googlegroups.com</a>><br> <b>Betreff:</b> [CP2K:15385] Unreasonable CELL_OPT result obtained for TiO2<u></u><u></u></span></p> </div> </div> <p class="MsoNormal"><u></u> <u></u></p> <p class="MsoNormal">Hello, cp2k developers and users,<u></u><u></u></p> <div> <p class="MsoNormal"><u></u> <u></u></p> <div> <p class="MsoNormal">I try to optimize primitive cell of rutile TiO2 by running CELL_OPT calculation at PBE+U(presently set to 0 eV)/DZVP level, but I find cell parameters deviate from experimental values quite quickly during calculation.<u></u><u></u></p> </div> <div> <p class="MsoNormal">I have tried changing STRESS_TENSOR to both NUMERICAL and ANALYTICAL but it does not help, I also think it may be not the reason why I get this kind of strange result.<u></u><u></u></p> </div> <div> <p class="MsoNormal">I attach my input script and CIF file below, are there any parameters in input script I forget?<u></u><u></u></p> </div> <div> <p class="MsoNormal">In addition, anatase TiO2 CELL_OPT task also has such problem, but I remember that primitive cell of Co3O4 can be successfully optimized.<u></u><u></u></p> </div> <div> <p class="MsoNormal"><u></u> <u></u></p> </div> <div> <p class="MsoNormal">Thanks in advance.<u></u><u></u></p> </div> </div> <div> <p class="MsoNormal"><u></u> <u></u></p> </div> <div> <p class="MsoNormal">Yike Huang<u></u><u></u></p> </div> </div></div></div><div lang="EN-US" link="blue" vlink="purple"><div><div style="border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt"><p class="MsoNormal">-- <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 data-email-masked rel="nofollow">cp...@googlegroups.com</a>.<br> To view this discussion on the web visit <a href="https://groups.google.com/d/msgid/cp2k/11f85e5a-b3f6-45b2-b164-11f12644f358n%40googlegroups.com?utm_medium=email&utm_source=footer" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=zh-CN&q=https://groups.google.com/d/msgid/cp2k/11f85e5a-b3f6-45b2-b164-11f12644f358n%2540googlegroups.com?utm_medium%3Demail%26utm_source%3Dfooter&source=gmail&ust=1621277494625000&usg=AFQjCNHenEHA_bZVrheFAk0kNonJo0M0bg"> https://groups.google.com/d/msgid/cp2k/11f85e5a-b3f6-45b2-b164-11f12644f358n%40googlegroups.com</a>.<u></u><u></u></p> </div> </div> </div> </blockquote></div>