<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hello,<div><br></div><div> I have a paramagnetic unit cell with a Re with an electron spin of 1 and three other non-paramagnetic ions. I have built a supercell and have run these calculations a few times using various number of kpoints, magnetic calculations with antiferromagnetic calculations, etc. However, I keep getting a fermi contact of zero, however I know that this is not real. Are there any known limitations in obtaining the fermi contact terms using this method for Re or Ru? I have also tried Ru and it predicts a rather large value which was slightly counter intuitive from the experimental value recorded. I am trying to compare these to experimentally determined data that were acquired using NMR, is this the best approach?</div><div><br></div><div>PS: Peter I thank you for your previous response however still having a few problems...</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span><font class="Apple-style-span" color="#0000FF">In ionic compounds, the Fermi contact term can sometimes be only a "small" part of the total Hyperfine field. The orbital (and dipolar)<br></font><span class="Apple-tab-span" style="white-space:pre"><font class="Apple-style-span" color="#0000FF"> </font></span><font class="Apple-style-span" color="#0000FF">terms can become large, even for 3d materials, in particular when the<br></font><span class="Apple-tab-span" style="white-space:pre"><font class="Apple-style-span" color="#0000FF"> </font></span><font class="Apple-style-span" color="#0000FF">electronic configuration contains eg. a single 3d electron in one<br></font><span class="Apple-tab-span" style="white-space:pre"><font class="Apple-style-span" color="#0000FF"> </font></span><font class="Apple-style-span" color="#0000FF">spin chanel (eg. high-spin Fe2+). I realize this and have looked into the dipolar and orbital terms however I don't seem to see an affect<br></font><span class="Apple-tab-span" style="white-space:pre"><font class="Apple-style-span" color="#0000FF"> </font></span><font class="Apple-style-span" color="#0000FF"><br></font><span class="Apple-tab-span" style="white-space:pre"><font class="Apple-style-span" color="#0000FF"> </font></span><font class="Apple-style-span" color="#0000FF">However, it is also well known that the contact term is often underestimated by about 10-20% for eg. Fe. - OK <br><br>Also be sure, you do the correct magnetic structure (often they are antiferromagnetic): I have tried this and gets me closure but still not what I was expecting</font></div><div><br></div><div><br></div><div>Regards,</div><div><br></div><div>Vlad</div></body></html>