<p>The first one is the BVS for the current lattice parameters. The second one allows for a correction corresponding to a contraction or expansion. By default the contraction iis close to how much larger than experiment PBE is. More accurately you can put in .latcalib a calibration of how much larger than experiment is the current lattice parameter, e.g. 1.005.</p>
<p>---------------------------<br>
Professor Laurence Marks<br>
Department of Materials Science and Engineering<br>
Northwestern University<br>
<a href="http://www.numis.northwestern.edu">www.numis.northwestern.edu</a> 1-847-491-3996<br>
"Research is to see what everybody else has seen, and to think what nobody else has thought"<br>
Albert Szent-Gyorgi<br>
</p>
<div class="gmail_quote">On Apr 16, 2013 4:04 AM, "Chang-Jong Kang" <<a href="mailto:cjkang87@gmail.com">cjkang87@gmail.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
<div dir="ltr">Dear Prof. Blaha and Wien2k users,
<div><br>
</div>
<div>When I saw case.outputnn file, there were two Bond-Valence Sum (BVS) printed like,</div>
<div><br>
</div>
<div>
<div>Atom 5 equiv 1 ATOM1 Bond-Valence Sum 2.62 2.77</div>
<div>Atom 5 equiv 2 ATOM1 Bond-Valence Sum 2.62 2.77</div>
<div>Atom 6 equiv 1 ATOM2 Bond-Valence Sum 2.48 2.62</div>
<div>Atom 6 equiv 2 ATOM2 Bond-Valence Sum 2.48 2.62</div>
<div>Atom 6 equiv 3 ATOM2 Bond-Valence Sum 2.48 2.62</div>
<div>Atom 6 equiv 4 ATOM2 Bond-Valence Sum 2.48 2.62</div>
<div>Atom 7 equiv 1 ATOM3 Bond-Valence Sum 2.16 2.28</div>
<div>Atom 7 equiv 2 ATOM3 Bond-Valence Sum 2.16 2.28</div>
<div>Atom 8 equiv 1 ATOM4 Bond-Valence Sum 2.30 2.43</div>
<div>Atom 8 equiv 2 ATOM4 Bond-Valence Sum 2.30 2.43</div>
<div>Atom 8 equiv 3 ATOM4 Bond-Valence Sum 2.30 2.43</div>
<div>Atom 8 equiv 4 ATOM4 Bond-Valence Sum 2.30 2.43</div>
<div><br>
</div>
<div>In nn.f source code, first and second value of BVS are named as "bva" and "bvaerr", respectively.</div>
<div><br>
</div>
<div>My question is</div>
<div>1. Which one is bond-valence sum?"</div>
<div>2. What is "bvaerr" parameter used in nn.f source file? Is it error of bond-valence sum?</div>
<div> Only difference between "bva" and "bvaerr" parameters is that</div>
<div> "bvaerr" use "DFTERR" parameter but "bva" does not use it.</div>
<div> However, when PBE funtional is used, "DFTERR" parameter is set to 1, so that</div>
<div> "bva" and "bvaerr" values are exactly same in my thought since I used PBE functional.</div>
<div><br>
</div>
<div>I am looking forward to your kind explanation.</div>
<div><br>
</div>
<div>Thanks.</div>
<div><br>
</div>
<div><br>
</div>
<div>Best wishes,</div>
<div>C.-J. Kang</div>
</div>
</div>
</div>
</blockquote></div>