<br>Thank you Ling. I had read this paper and noticed this problem before. I had even asked a similar question before on here, but the manifestation was slow convergence rather than divergence. I did not know that any of these optFIT basis sets were available.<div><br></div><div>Using the optFIT you provided, I was able to converge alpha boron without much issue. Do you know of any other issues where this might pop-up? i.e. is this just an issue of boron and carbon?<br><div><br></div><div><br></div></div><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Thursday, January 20, 2022 at 2:36:57 AM UTC-8 S Ling 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;"><div dir="ltr">Hi Nick,<div><br></div><div>If you read the original paper of ADMM (<a href="https://pubs.acs.org/doi/10.1021/ct1002225" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://pubs.acs.org/doi/10.1021/ct1002225&source=gmail&ust=1642782838738000&usg=AFQjCNGKc9PaPLA7pjyeKBlnnbzlPa2Axg">https://pubs.acs.org/doi/10.1021/ct1002225</a> ), they mentioned "the condition number of the overlap matrix with the FIT3 basis is unfavorable in the case of bulk C", see section 3.6. They produced a separate optFIT3 basis for C with much more favourable condition number. Unfortunately, I cannot find the optFIT3 basis for C. I have personally produced an optFIT3 basis for B if you want to try.</div><div><br></div><div>SL</div><div><br></div><div>#####</div><div><p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif">B OPTFIT3</p>
<p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif">6</p>
<p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif">1 0 0 1 1</p>
<p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif">
0.27763115800007 1.00000000000000E+00</p>
<p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif">1 0 0 1 1</p>
<p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif">
3.17679618980955 1.00000000000000E+00</p>
<p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif">1 0 0 1 1</p>
<p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif">
8.21086367916339 1.00000000000000E+00</p>
<p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif">1 1 1 1 1</p>
<p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif"> 0.15104423596280
1.00000000000000E+00</p>
<p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif">1 1 1 1 1</p>
<p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif">
0.61295240465023 1.00000000000000E+00</p>
<p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif">1 1 1 1 1</p>
<p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif">
2.56244918405309 1.00000000000000E+00</p>
<p class="MsoNormal" style="margin:0cm;font-size:11pt;font-family:Calibri,sans-serif">##### </p></div></div><br><div class="gmail_quote"></div><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, 20 Jan 2022 at 03:24, Nicholas Winner <<a href data-email-masked rel="nofollow">nwi...@berkeley.edu</a>> wrote:<br></div></div><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">I've been looking at a couple of systems that are atomically pretty dense. For example, alpha boron and diamond.<div><br></div><div>For these systems, when I increase the supercell size too large, the energy in the SCF loop explodes to ridiculous values. For example, I am calculating diamond with 54 atom and 128 atom supercells, truncated PBE0 with 2A cutoff. </div><div><br></div><div>The 54 atom case converges with no real issues. In that case I have used OT, and against common wisdom for really accurate results I screen on the initial density matrix with scf_guess atomic. The convergence seems robust to that and the aggressive (1e-6) integral screening.</div><div><br></div><div>Then, I move to 128 atom supercells, and I am unable to converge as the energies diverge rapidly after a few SCF steps. For this case, I have stopped screening on the initial density matrix. I was able to narrow the issue down to the auxiliary basis sets used for C. I tried cFIT3, pFIT3, cpFIT3, and FIT3, which all result in the rapid divergence of the energy. Example:</div><div><p><br></p>
<p> 1 OT CG 0.15E+00 141.5 0.01764397 -673.6622732538 -6.74E+02</p>
<p> 2 OT LS 0.60E+00 35.1 -806.4853195301</p>
<p> 3 OT CG 0.60E+00 38.5 12.03779293 -4186.8334161380 -3.51E+03</p>
<p> 4 OT LS 0.30E+00 33.7 -8657.0632214970</p></div><div><br></div><div>Since these all failed, but the primary basis is prohibitively large, I tried setting BASIS_SET AUX_FIT SZV-MOLOPT-SR-GTH, and this remedies the problem, and the calculation finishes.<br></div><div><br></div><div>My questions then are four-fold.</div><div>(1) Is this behavior for dense systems like diamond expected? I have not had this issue with any other system besides alpha boron.</div><div>(2) Is this un-fixable? i.e. we can't use the FIT basis sets for such systems?</div><div>(3) Would someone have another idea for why this is the case? i.e. maybe FIT basis sets can still be used if some other setting was changed. </div><div>and finally (4) Does anyone see an issue with proceeding with using the SZV basis as the auxiliary basis?</div><div><br></div><div>-Nick</div><div><br></div>
<p></p></blockquote></div><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">
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