<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=ISO-8859-1">
<title></title>
</head>
<body text="#000000" bgcolor="#ffffff">
Dear Ari,<br>
<br>
can you give me a reference for this "constant energy term dropped when
eigenvalues are calculated".<br>
This probably also explains the shift of the eigenvalues as a function
of cell size.<br>
<br>
Thank you<br>
<br>
Walter Langel<br>
<br>
Ari P Seitsonen wrote:<br>
<blockquote type="cite"
cite="midPine.LNX.4.58.0411281818350.21637@pcihserv.unizh.ch">
<pre wrap="">Dear Eung-Gun,
I write what I know, some one please correct and add: In order to get the
correct eigenvalues you need to have the reference, that is, vacuum,
somewhere in your system. So you can have 2-dimensional (surface = slab
geometry), 1D (line) or 0D (isolated system). When you have performed your
calculation you check the value of the electro-static potential in the
(middle of) vacuum region, and subtract that from the eigenvalues.
Greetings (again/still) from Zurich,
apsi
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
Ari Paavo Seitsonen / <a class="moz-txt-link-abbreviated" href="mailto:Ari.P.Seitsonen@iki.fi">Ari.P.Seitsonen@iki.fi</a> / <a class="moz-txt-link-freetext" href="http://www.iki.fi/~apsi/">http://www.iki.fi/~apsi/</a>
Tel +41 1 635 44 97 / Fax +41 1 635 68 38 / GSM +41 79 719 09 35
Anschrift: Physikalisch Chemisches Institut (PCI), Universität Zürich (UniZh)
Indirizzo: Winterthurerstrasse 190, CH-8057 Zürich
Address: Schweiz / Svizzera / Suisse / Svizra / Switzerland
On Wed, 24 Nov 2004, Eung-Gun Kim wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Dear List Subscribers,
I was told that in most plane-wave/pseudopotential codes, there is a constant
energy term dropped when eigenvalues are calculated. For most purposes where
only the energy difference matters, one would not need this dropped term.
However, in
some instances, for example, when one calculates the work function OR compares
HOMO/LUMO levels between two different molecules, this dropped term is to be
recovered. Is there a way to retrieve this missing term to obtain "true"
eigenvalues? Thanks very much for reading.
Best regards,
EG Kim
_______________________________________________
CPMD-list mailing list
<a class="moz-txt-link-abbreviated" href="mailto:CPMD-list@cpmd.org">CPMD-list@cpmd.org</a>
<a class="moz-txt-link-freetext" href="http://cpmd.org/mailman/listinfo/cpmd-list">http://cpmd.org/mailman/listinfo/cpmd-list</a>
</pre>
</blockquote>
<pre wrap=""><!---->_______________________________________________
CPMD-list mailing list
<a class="moz-txt-link-abbreviated" href="mailto:CPMD-list@cpmd.org">CPMD-list@cpmd.org</a>
<a class="moz-txt-link-freetext" href="http://cpmd.org/mailman/listinfo/cpmd-list">http://cpmd.org/mailman/listinfo/cpmd-list</a>
</pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Prof. Dr. Walter Langel
Institut fuer Chemie und Biochemie
Universitaet Greifswald
Soldmannstrasse 23
D-17487 Greifswald
Germany
Tel +49 3834 86 4423
Fax +49 3834 86 4413
<a class="moz-txt-link-freetext" href="http://www.chemie.uni-greifswald.de/~plasma">http://www.chemie.uni-greifswald.de/~plasma</a>
</pre>
</body>
</html>