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    <p>Well, the main explanation is quite simple: Of course you have to
      use IDENTICAL RMTs for the 2 calculations.</p>
    <p>I can see 1.97 and 2.23  for Ru and 1.61 and 1.17 for N. <br>
    </p>
    <p>This is as if you would use 2 different pseudopotentials and
      compare the energies.</p>
    <p>Since the N2 forces you to use small N spheres, you have to use
      them allways. The Ru should be chosen according to the minimum
      distances. Everything between 2.0 and 2.2 is probably fine.</p>
    <p>I'd even start with RKmax=5.5, but eventually increase it to 6 or
      6.5 later to check if the total energy difference remains
      constant.<br>
    </p>
    <p>In addition your cell is  "funny".  Why would you use such a
      rectangular cell with 20 and 10 bohr ???</p>
    <p>And, as already mentioned by L.Marks, in WIEN2k it is much more
      efficient to use slabs with inversion symmetry, which can be
      easily obtained by putting the N atoms on both sides of the slab.</p>
    <p>You probably started with a GPAW structure, but WIEN2k has very
      nice tools to make such calculations.</p>
    <p>You should first optimize the bulk Ru structure (at least the
      volume). Using the lowest energy structure you can easily create
      surface slabs with     x supercells  (to start with I'd suggest a
      3x3x2 or 3x3x3 supercell), and then put a N2 molecule by hand on
      both sides of the slab keeping inversion symmetry.</p>
    <p>run_law -fc 10; save unrelaxed; run_lapw -min;   save relaxed</p>
    <p>In the same directory, you could now</p>
    <p> i) manually move the 2 N atoms apart and do the same steps as
      before</p>
    <p>ii) use the "constraints" option of mixer to increase the N-N
      distance to a large (desired) value. This option even allows you
      to get the barrier height, not just the energy of the starting and
      final structures. It may need some fine-tuning of some input
      parameters, but when you watch the N-N distances (and the
      energies) during the run you should be able to make it.</p>
    <p>Regards</p>
    <p>Peter Blaha<br>
    </p>
    <div class="moz-cite-prefix">Am 11.05.2022 um 08:57 schrieb Gargee
      Bhattacharyya:<br>
    </div>
    <blockquote type="cite"
cite="mid:CAGxNEp_9T6C+w7wmVOcJoM=+vjZHe1-VxCp7+L_-7+yo_mgvNQ@mail.gmail.com">
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        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small">Dear
          Developers, </div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><br>
        </div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small">I am a
          new user of WIEN2k. I am using WIEN2k version 18.2 running on
          slurm cluster. I am <span
            style="font-family:Arial,Helvetica,sans-serif">using the
            following command in my slurm job script:</span> </div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><br>
        </div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><b>run_lapw
            -NI -ec 0.0001 -cc 0.01 >& job_stats.txt</b><br>
        </div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><br>
        </div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><br>
        </div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small">I am
          trying to compare barrier height for N2 dissociation on the Ru
          (0001) surface. Using GPAW, previously I have optimized N2
          adsorbed Ru slab with N-N distance 1.242 Å and 2N adsorbed Ru
          slab with N-N distance <span
            style="font-family:Arial,Helvetica,sans-serif">2.701 Å using
            K mesh 3*6*1. I have calculated the energy difference as: <b>1.39
              eV.</b> My question is:</span></div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><span
            style="font-family:Arial,Helvetica,sans-serif"><br>
          </span></div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><span
            style="font-family:Arial,Helvetica,sans-serif">1. When I am
            running scf calculation with the optimized structures and
            comparing the energy difference, I am not getting the same.
            I have used the same two structures and used 3*6*1 non
            shifted K mesh. The total energy difference I found was :
            0.0416 Ry = <b>0.57 eV</b></span></div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><span
            style="font-family:Arial,Helvetica,sans-serif">I am using
            non-spin polarized calculations and using LDA exchange
            functional. </span></div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><span
            style="font-family:Arial,Helvetica,sans-serif"><br>
          </span></div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><span
            style="font-family:Arial,Helvetica,sans-serif">The initial
            structure (</span>N2 adsorbed Ru<span
            style="font-family:Arial,Helvetica,sans-serif">) and final
            structure (</span>2N adsorbed Ru<span
            style="font-family:Arial,Helvetica,sans-serif">) are
            attached herewith. </span></div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><span
            style="font-family:Arial,Helvetica,sans-serif"><br>
          </span></div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small">It would
          be helpful if you let me know whether I have done anything
          wrong in the calculation so that I can compare the energy
          difference GPAW and Win2k.<span
            style="font-family:Arial,Helvetica,sans-serif"><br>
          </span></div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><span
            style="font-family:Arial,Helvetica,sans-serif"><br>
          </span></div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><span
            style="font-family:Arial,Helvetica,sans-serif"><br>
          </span></div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><span
            style="font-family:Arial,Helvetica,sans-serif">Kind regards</span></div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><span
            style="font-family:Arial,Helvetica,sans-serif">Gargee</span></div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><br>
        </div>
        <div class="gmail_default"
          style="font-family:arial,sans-serif;font-size:small"><br>
        </div>
        <div><br>
        </div>
        -- <br>
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          data-smartmail="gmail_signature">
          <div dir="ltr">
            <div>
              <div dir="ltr">
                <div dir="ltr">Kind regards<br>
                  <div>Gargee Bhattacharyya<br>
                  </div>
                  <div><span>
                      <div
style="margin:0px;font-size:13px;font-family:Arial,sans-serif;color:rgb(32,31,30);text-align:start;background-color:rgb(255,255,255)"><span
style="margin:0px;font-size:small;font-family:Arial,Helvetica,sans-serif;color:black">Postdoctoral
                          Fellow<br>
                        </span></div>
                      <div dir="ltr"
style="margin:0px;font-size:15px;font-family:Calibri,Arial,Helvetica,sans-serif;color:rgb(32,31,30);text-align:start;background-color:rgb(255,255,255)"><font
                          size="2" face="Arial,Helvetica,sans-serif">
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                          style="margin:0px;font-size:13px;font-family:Arial,sans-serif"><font
                            style="color:rgb(34,34,34)" size="2"
                            face="Arial,Helvetica,sans-serif"><span
                              style="margin:0px;color:black"></span></font>
                          <div style="margin:0px;color:black"><font
                              size="2" face="Arial,Helvetica,sans-serif">Department
                              of Physics and Astronomy</font></div>
                          <div style="margin:0px;color:black"><font
                              size="2" face="Arial,Helvetica,sans-serif">Aarhus
                              University<br>
                            </font></div>
                          <div style="margin:0px;color:black"><span
style="margin:0px;font-size:small;font-family:Arial,Helvetica,sans-serif">Ny
                              Munkegade 120</span></div>
                          <div style="margin:0px;color:black"><span
style="margin:0px;font-size:small;font-family:Arial,Helvetica,sans-serif">8000
                              Aarhus C <br>
                            </span></div>
                          <div style="margin:0px;color:black"><span
style="margin:0px;font-size:small;font-family:Arial,Helvetica,sans-serif">Denmark<br>
                            </span></div>
                        </div>
                      </div>
                    </span></div>
                  <div><br>
                  </div>
                  <br>
                </div>
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      <br>
      <fieldset class="moz-mime-attachment-header"></fieldset>
      <pre class="moz-quote-pre" wrap="">_______________________________________________
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</pre>
    </blockquote>
    <pre class="moz-signature" cols="72">-- 
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Peter Blaha,  Inst. f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-158801165300
Email: <a class="moz-txt-link-abbreviated" href="mailto:peter.blaha@tuwien.ac.at">peter.blaha@tuwien.ac.at</a>          
WWW:   <a class="moz-txt-link-freetext" href="http://www.imc.tuwien.ac.at">http://www.imc.tuwien.ac.at</a>      WIEN2k: <a class="moz-txt-link-freetext" href="http://www.wien2k.at">http://www.wien2k.at</a>
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