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On 02/05/2014 10:56 AM, Ganjar Kurniawan wrote:<br>
<blockquote
cite="mid:1391594195.5270.YahooMailNeo@web160701.mail.bf1.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff;
font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial,
Lucida Grande, Sans-Serif;font-size:12pt">I am trying to compare
the calculation of the Lithium bulk system which has BCC
structure with lattice constant is 6.597 bohr using different
pseudopotential between Li.pbe-s-rrkjus_psl.0.2.1.UPF and
Li.pw91-n-van.UPF.
<div><br>
</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,Sans-Serif; background-color: transparent; font-style:
normal;">the result give different of total energy are
-14.82521305 Ry and -1.82426227 Ry respectively...</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,Sans-Serif; background-color: transparent; font-style:
normal;"><br>
</div>
<div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida
Grande,Sans-Serif; background-color: transparent; font-style:
normal;">The question is why this is happen??? anyone can to
explain it???</div>
<br>
</div>
</blockquote>
Dear Ganjar,<br>
as often repeated, the absolute value of the total energy has no
meaning in periodic boundary condition and pseudopotential
calculations. Only relative energy, computed with strictly the same
setup have physical meaning.<br>
<br>
I.e. in your case you an compare the energy of bulk Lithium with
that of isolated Lithium atoms, computed with the same pseudo and
cutoff. This would give you the binding energy of your crystal.<br>
<br>
kind regards<br>
<br>
<pre class="moz-signature" cols="72">--
Dr. Lorenzo Paulatto
IdR @ IMPMC -- CNRS & Université Paris 6
+33 (0)1 44 275 084 / skype: paulatz
<a class="moz-txt-link-freetext" href="http://www-int.impmc.upmc.fr/~paulatto/">http://www-int.impmc.upmc.fr/~paulatto/</a>
23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05
</pre>
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