<div dir="ltr">Hi
Vladimir, <div><br>Thanks for the response! What would you say about the difference in ideal and single determinant spin states that are Delta_S**2 = ~0.1-0.2? I have a few calculations where the ideal S**2 is 6.00000 and the single determinant S**2 is 6.150000. </div><div><br></div><div>I found a rule for Gaussian calculations where the difference should be less than 10% of the ideal S**2. However, is that a reasonable assertion for all UKS DFT calculations? </div><div><br>With much appreciation, </div><div><br>Stephen </div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Jan 25, 2021 at 6:50 AM Vladimir Rybkin <<a href="mailto:rybk...@gmail.com">rybk...@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Dear Stephen,<div><br></div><div>the "cutoff" is what you find reasonable. To me, 12.019722 is practically no contamination, whereas delta=2.0 is a large one and the results are likely unreasonable. At least, you will not likely be able to get the latter published.</div><div><br></div><div>Yours,</div><div><br></div><div>Vladimir</div><div><br></div><div class="gmail_quote"><div dir="auto" class="gmail_attr">пятница, 22 января 2021 г. в 20:55:03 UTC+1, Stephen: <br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi All, <div><br></div><div>I'm performing a few calculations of Ni(II) atom supported on a metal-organic framework. The Ni(II) atoms can exhibit different spin states, which means I must run UKS T while varying MULTI to account for all the configurations. </div><div><br></div><div>Is there a specific rule for spin contamination when looking at the S**2? For example, </div><div><br><div><font face="Verdana"> Ideal and single determinant S**2 : 12.000000 12.019722</font></div></div><div><br></div><div>I've assumed that this particular structure has no spin contamination, I have some other calculations where the difference between the ideal and single determinant spin states is much larger (Delta_S**2 = ~2.00). <br><br>Does anyone have an appropriate cutoff for spin contamination? </div><div><br></div><div>With much appreciation, <br><br>Stephen </div></blockquote></div>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div><i><font color="#000000" face="arial, sans-serif"><b>Stephen P. Vicchio</b></font></i></div><div><font color="#000000" face="arial, sans-serif">PhD Candidate | Getman Research Group</font></div><font color="#000000" face="arial, sans-serif">Dept. of Education GAANN Fellow</font></div><div dir="ltr"><font face="arial, sans-serif"><span style="color:rgb(51,51,51);text-align:center">Director of Student Organization Finances, Graduate Student Government</span><font color="#000000"><br></font></font></div><div dir="ltr"><a href="https://www.clemson.edu/cecas/departments/chbe/" target="_blank"><font face="arial, sans-serif">Department of Chemical & Biomolecular Engineering</font></a></div><div dir="ltr"><font color="#000000" face="arial, sans-serif">105 Earle Hall | Clemson, SC 29634-0909</font></div><div dir="ltr"><a href="mailto:svi...@g.clemson.edu" target="_blank"><font face="arial, sans-serif">svi...@g.clemson.edu</font><br></a><br></div></div></div></div></div>