<div dir="ltr"><div>Thanks for the reply and the PP.</div><div><br></div>I had hoped to get close here given Mali et al. reported such excellent agreement for this exact system using your code in 2010. Though thanks for the hint tip that I may not find continued agreement with other systems at this level of theory. <div><div><br></div><div>I tried the alternate PP you sent and get somewhat different results, though the two calculations are closer to each other than either is to the experiment. Perhaps this suggests I am doing something wrong?</div></div><div><br></div><div>The Capsoni paper I mentioned has:</div><div>Li1: A = 4.32 MHz</div><div>Li2/Li3: A = 2.13 MHz/ 2.07 MHz (crystallographically very similar)</div><div><br></div><div>Reading chemical shifts from Fig. 4 of Mali et al's Quantum Espresso calculations and using their Eq. 1 (approximate as magnetic susceptibility not known) to convert A values yields:</div><div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial">Li1: delta = 1425 ppm --> A = 4.14 MHz</div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial">Li2/Li3: delta = 800/760 ppm --> A = 2.33/2.21 MHz (for the 2 sites)</div><br></div><div>The results I get with this new PP are (Li1 here is the site well-known to have the larger A value):</div><div><div> ----- Fermi contact in MHz -----</div><div> bare GIPAW core-relax total</div><div> Li 1 -9.209256 8.650557 0.000000 -0.558699</div><div> Li 2 -12.302726 4.367716 0.000000 -7.935010</div><div> Li 3 -12.374583 4.261266 0.000000 -8.113317</div></div><div><br></div><div>They aren't too sensitive to ecutwfc. Interestingly, the "GIPAW" term is nearly exactly double the correct answer. I sort-of get the idea of your core-relaxation theory, but I haven't managed to read anything to understand the breakdown into the "bare" vs "GIPAW" components.</div><div><br></div><div>thanks for any further insight,</div><div>Kris</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Apr 18, 2018 at 7:19 AM, Davide Ceresoli <span dir="ltr"><<a href="mailto:davide.ceresoli@cnr.it" target="_blank">davide.ceresoli@cnr.it</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<p>Dear Kris,<br>
the core-relaxation feature of GIPAW is extremely experimental.<br>
It's based on a perturbation approach which might not be adequate<br>
in all cases.</p>
<p>Could you try with the attached pseudopotential? this one has 3 valence<br>
electrons for Li and a cutoff between 120 and 150 Ry should be sufficient.<br>
This way, the polarization of the 1s electrons should be described at a<br>
better level.</p>
<p>However, we are also working on similar Li-battery materials, comparing to<br>
experiments and Crystal14+B3LYP calculations, and in some cases we are<br>
not able to reproduce the Li hyperfine cc.<br>
</p>
<p>Good luck for your calculations.</p><span class="HOEnZb"><font color="#888888">
<p>Davide<br>
</p>
<br>
<div class="m_5208189556347929124moz-signature">-- <br>
<hr>
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<br>
<br>
On 04/17/2018 06:45 PM, Kris Harris wrote:<br>
<blockquote type="cite">
<div dir="ltr">Hi,
<div><br>
</div>
<div>I'm starting out with QE and am attempting to learn by repeating some literature results for hyperfine coupling constants for Li in Li2MnO3.</div>
<div><br>
</div>
<div>Capsoni et. al in 1997 Phys. Rev. B. list the experimental value for A as 4.31 MHz for one site (there are 2 other sites at essentially half that A)</div>
<div><br>
</div>
<div>Mali. et al. were able to reproduce that value very well in Chem. Comm. in 2010 (DOI:10.1039/c003065a) using QE with the GIPAW module. I'm attempting to reproduce that result, following their method as close as possible.</div>
<div><br>
</div>
<div>I used dist.x to attempt to verify the structure, and did some convergence tests with respect to <span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">ecutwfc
and k-points to make sure the calculations was reasonable. I also verified that the binary I have reproduced the H2O+ test case included in the distribution.</span></div>
<div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br>
</span></div>
<div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">The
result I get is quite a long ways off (0.06 MHz and -7 MHz instead of ~4.3 and ~2.15 MHz).</span></div>
<div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br>
</span></div>
<div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">Any
help on what I've managed to do wrong here would be greatly appreciated.</span></div>
<div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br>
</span></div>
<div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br>
</span></div>
<br>
</div>
</blockquote>
<br>
</span></div>
</blockquote></div><br></div>