<div dir="ltr">Dear Matthias,<div><br></div><div>Many thanks for your reply! I will check the 3d occupations. As you mentioned, the result converged to different states for the same configuration, I am wondering if the SCF threshold is too large in this case. The previous EPS_SCF was 1.0E-7, I am going to try a smaller threshold for a more accurate result.<br><br>Thanks again for your help!</div><div><br></div><div>Best Regards,</div><div><br></div><div>Xiaohui<br><br>在 2018年4月1日星期日 UTC+8下午11:13:16，Matthias Krack写道：<blockquote class="gmail_quote" style="margin: 0;margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;"> <div lang="EN-GB" link="blue" vlink="purple"> <div> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Dear Xiaohui</span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">It seems the two DFT+U runs converged to different states for the same atomic configuration, since band gaps and spin densities are quite different. The Hubbard U term promotes an electron localisation, in your case of the Ti 3d electrons. Different 3d orbital occupation patterns can result in different total energies, especially for large U values. You can check the 3d occupations by activating the &PLUS_U print section in &FORCE_EVAL/&DFT/&PRINT.</span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Best regards</span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Matthias</span></p> <p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p> <p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> <a href="javascript:" target="_blank" gdf-obfuscated-mailto="5lLVnlnmBAAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">cp...@googlegroups.com</a> [mailto:<a href="javascript:" target="_blank" gdf-obfuscated-mailto="5lLVnlnmBAAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">cp...@googlegroups.com</a>] <b>On Behalf Of </b>Xiaohui Yang<br> <b>Sent:</b> 01 April 2018 14:24<br> <b>To:</b> cp2k<br> <b>Subject:</b> [CP2K:10136] DFT+U calculation problems</span></p> <p class="MsoNormal"> </p> <div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545">Dear</span><span style="font-size:9.0pt;font-family:".PingFang SC","serif";color:#454545">,</span><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545"> all</span><span style="font-size:9.0pt;color:#454545"></span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545"> </span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545">I did some calculations with DFT+U functional recently, they all obtained from the CP2K program. </span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545"> </span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545">At first, I calculated the geometry optimization of the structre, and obtained the total energy directly from the last optimized structure (let's say E1). Then</span><span style="font-size:9.0pt;font-family:".PingFang SC","serif";color:#454545">,</span><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545"> I ran a single point energy calculation with the same optimized structure and got the total energy E2. </span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545"> </span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545">However, those two total energies (E1 & E2) I collected from the exact same structure have significant difference</span><span style="font-size:9.0pt;font-family:".PingFang SC","serif";color:#454545">,</span><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545"> E2-E1 = 1.2 eV. </span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545"> </span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545">When checking their output results</span><span style="font-size:9.0pt;font-family:".PingFang SC","serif";color:#454545">,</span><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545"> I find that the total energy difference could be attributed to two parts, DFT+U energy and Core Hamiltonian energy. The input and output files are attached below. </span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545"> </span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545">As far as I know</span><span style="font-size:9.0pt;font-family:".PingFang SC","serif";color:#454545">,</span><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545"> the total energy calculated from the same settings and structures should be the same. I have no idea about these results. Could you please help me check what is wrong with my calculation? Any comments will be greatly appreciated. </span><span style="font-size:9.0pt;color:#454545"></span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;color:#454545"> </span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545">Best Regards,</span><span style="font-size:9.0pt;color:#454545"></span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;color:#454545"> </span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Helvetica Neue","serif";color:#454545">Xiaohui</span><span style="font-size:9.0pt;color:#454545"></span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;color:#454545"> </span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;color:#454545"> </span></p> </div> <div> <p class="MsoNormal"><span style="font-size:9.0pt;color:#454545"> </span></p> </div> </div> <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="javascript:" target="_blank" gdf-obfuscated-mailto="5lLVnlnmBAAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">cp2k+uns...@googlegroups.<wbr>com</a>.<br> To post to this group, send email to <a href="javascript:" target="_blank" gdf-obfuscated-mailto="5lLVnlnmBAAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">cp...@googlegroups.com</a>.<br> Visit this group at <a href="https://groups.google.com/group/cp2k" target="_blank" rel="nofollow" onmousedown="this.href='https://groups.google.com/group/cp2k';return true;" onclick="this.href='https://groups.google.com/group/cp2k';return true;">https://groups.google.com/<wbr>group/cp2k</a>.<br> For more options, visit <a href="https://groups.google.com/d/optout" target="_blank" rel="nofollow" onmousedown="this.href='https://groups.google.com/d/optout';return true;" onclick="this.href='https://groups.google.com/d/optout';return true;">https://groups.google.com/d/<wbr>optout</a>.</p> </div> </div> </blockquote></div></div>