<div dir="ltr">Thank you very much for your <span style="color:rgb(33,33,33);font-family:inherit;white-space:pre-wrap">detailed response.</span></div><div class="gmail_extra"><br><div class="gmail_quote">2017-03-28 3:48 GMT+02:00 Gavin Abo <span dir="ltr"><<a href="mailto:gsabo@crimson.ua.edu" target="_blank">gsabo@crimson.ua.edu</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
  
    
  
  <div bgcolor="#FFFFFF" text="#000000">
    <div class="m_7544408896199275156moz-cite-prefix">The NiO example [1] with 1 k-point gave
      about 6 eV with the NiO_+.5-1 calculation taking about 36 cycles
      [2,3].  N.B. [4], this is with 2.00 and not 20.3 in case.in1.  I
      believe the 20.3 in the paper may be a typographical error. At the
      bottom of [1], there is the statement:<br>
      <br>
      Usually, it is better to just set the d energy 2-4 Ry above the
      Fermi level.<br>
      <br>
      The Fermi level is not known when starting the calculation, but a
      small value of about 0 is likely a reasonable assumption.  So let
      Fermi level = 0.  Taking the lower value of 2 Ry from the
      statement above.  So took 2.00 for case.in1.  I think the Fermi
      level obtained after the calculation was about 0.5. If you round
      that down, it becomes zero.  So it seems the 0 was likely an okay
      starting assumption.<br>
      <br>
      I suspect 1 k-point and 5 RKmax wouldn't be used if it was a
      proper calculation, but the paper is an example such that it was
      likely chosen for speed [5].<br>
      <br>
      For example, it looks like 100 k-points and 5.7 RKmax (instead of
      1 k-point and 5 RKmax) were used in G. K. H. Madsen and P. Novak
      calculation for Fe3O4 [6].<br>
      <br>
      Keep in mind that the Ueff values obtained from the Constrained
      method are known to be of questionable accuracy [7].<br>
      <br>
      Rather than your two choices below, it is better to do convergence
      tests [8-12].<br>
      <br>
      [1]
      <a class="m_7544408896199275156moz-txt-link-freetext" href="http://susi.theochem.tuwien.ac.at/reg_user/textbooks/Constraint_U.pdf" target="_blank">http://susi.theochem.tuwien.<wbr>ac.at/reg_user/textbooks/<wbr>Constraint_U.pdf</a><br>
      [2]
<a class="m_7544408896199275156moz-txt-link-freetext" href="http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg14460.html" target="_blank">http://www.mail-archive.com/<wbr>wien@zeus.theochem.tuwien.ac.<wbr>at/msg14460.html</a><br>
      [3]
<a class="m_7544408896199275156moz-txt-link-freetext" href="http://wien2k-algerien1970.blogspot.com/2016/08/how-to-calculate-u-parameter-in-nickel.html" target="_blank">http://wien2k-algerien1970.<wbr>blogspot.com/2016/08/how-to-<wbr>calculate-u-parameter-in-<wbr>nickel.html</a><br>
      [4] <a class="m_7544408896199275156moz-txt-link-freetext" href="https://en.wikipedia.org/wiki/Nota_bene" target="_blank">https://en.wikipedia.org/wiki/<wbr>Nota_bene</a><br>
      [5]
<a class="m_7544408896199275156moz-txt-link-freetext" href="http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg15593.html" target="_blank">http://www.mail-archive.com/<wbr>wien@zeus.theochem.tuwien.ac.<wbr>at/msg15593.html</a><br>
      [6] <a class="m_7544408896199275156moz-txt-link-freetext" href="https://arxiv.org/abs/cond-mat/0412560v1" target="_blank">https://arxiv.org/abs/cond-<wbr>mat/0412560v1</a><br>
      [7]
<a class="m_7544408896199275156moz-txt-link-freetext" href="http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg12429.html" target="_blank">http://www.mail-archive.com/<wbr>wien@zeus.theochem.tuwien.ac.<wbr>at/msg12429.html</a><br>
      [8]
<a class="m_7544408896199275156moz-txt-link-freetext" href="http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg15596.html" target="_blank">http://www.mail-archive.com/<wbr>wien@zeus.theochem.tuwien.ac.<wbr>at/msg15596.html</a><br>
      [9]
<a class="m_7544408896199275156moz-txt-link-freetext" href="http://wien2k-algerien1970.blogspot.com/2016/08/kpoint-convergence-test.html" target="_blank">http://wien2k-algerien1970.<wbr>blogspot.com/2016/08/kpoint-<wbr>convergence-test.html</a><br>
      [10]
<a class="m_7544408896199275156moz-txt-link-freetext" href="https://www.beilstein-journals.org/bjnano/content/supplementary/2190-4286-2-45-S1.pdf" target="_blank">https://www.beilstein-<wbr>journals.org/bjnano/content/<wbr>supplementary/2190-4286-2-45-<wbr>S1.pdf</a><br>
      [11]
<a class="m_7544408896199275156moz-txt-link-freetext" href="http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg01700.html" target="_blank">http://www.mail-archive.com/<wbr>wien%40zeus.theochem.tuwien.<wbr>ac.at/msg01700.html</a><br>
      [12]
<a class="m_7544408896199275156moz-txt-link-freetext" href="http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg08186.html" target="_blank">http://www.mail-archive.com/<wbr>wien%40zeus.theochem.tuwien.<wbr>ac.at/msg08186.html</a>
      <br><span class="">
      <br>
      On 3/27/2017 9:50 AM, karima Physique wrote:<br>
    </span></div><span class="">
    <blockquote type="cite">
      <div dir="ltr">Thank you for your answer but i I noticed that Ueff
        is very sensitive with the change of RKmax and Kpoint it is for
        this I evoked this subject abd  for example
        <div>For K = 1 and RKmax 5 i found Ueff = 3.6 eV</div>
        <div>But For K = 100 Points and RKmax 8.5 i found Ueff = 5.4 eV</div>
        <div><br>
        </div>
        <div>5.4 and 3.6 are relatively far </div>
        <div><br>
        </div>
        <div>What I really ask is that the choice of one point is it
          mandatory? (as is indicated in the paper of <span style="color:rgb(80,0,80);font-size:12.8px">G. K. H. Madsen
            and P. Novak</span>) or else I have to force these
          parameters (a large number of Kpoint and rkmax> 7) which of
          these two choices is good</div>
      </div>
    </blockquote>
    <span></span>
  </span></div>

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