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<p>Dear Ghadiyali Mohammed Kader,</p>
<p><br>
</p>
<p>the paper by Meyer and Vanderbilt does include a discussion about
the "dipole correction".</p>
<p>The whole story (why a dipole correction is needed) is actually a
little bit more involved and</p>
<p>not so important - you just need to know, that if you want to
simulate a system in an electric</p>
<p>field, you also need to switch on the dipole correction in most
cases.</p>
<p><br>
</p>
<p>Irrelevant details:</p>
<p><br>
</p>
<p>- Neugebauer and Scheffler wanted to simulate the adsorption of
Na and K on Ag(111)</p>
<p> (paper: Phys. Rev. B 46, 16067 (1992))</p>
<p>- to compensate the dipole within the system (to be able to use a
3D-periodic boundary code)</p>
<p> they introduced an external electric field (the sawtooth
potential)</p>
<p>- Bengtsson showed that in this case it is actually not
"external" but has an "internal" origin</p>
<p> and that's why you have to multiply it by a factor of 1/2</p>
<p> (paper: Phys. Rev. B 59, 12301 (1999))</p>
<p>- the paper by Meyer and Vanderbilt is more or less a summary of
these details, i.e., that</p>
<p> for the internal dipole (also the one induced by the external
field) you have a slightly different</p>
<p> equation (the prefactor and the internal dipole needs to be
recalculated each scf step as the</p>
<p> density changes)<br>
</p>
<p>- in VASP they actually don't cite the paper by Bengtsson but
only state that a more general</p>
<p> approach is chosen which does not include the mistake of the
Neugebauer/Scheffler paper<br>
</p>
<p><br>
</p>
<p>Regards</p>
<p><br>
</p>
<p>Thomas<br>
</p>
<br>
<div class="moz-cite-prefix">On 08.01.2018 13:36, Mohammed Ghadiyali
wrote:<br>
</div>
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<p style="margin-top:0;margin-bottom:0">Respected Sir,</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">Thank you for the
inputs.</p>
<p style="margin-top:0;margin-bottom:0"><span style="font-size:
12pt;">Can you suggest any paper/s where the dipole
interaction is explained?</span><br>
</p>
<p style="margin-top:0;margin-bottom:0"><span style="font-size:
12pt;">The paper by Meyer and Vanderbilt do not cover it.</span></p>
<p style="margin-top:0;margin-bottom:0"><span style="font-size:
12pt;"><br>
</span></p>
<p style="margin-top:0;margin-bottom:0"><span style="font-size:
12pt;">Regards,</span></p>
<p style="margin-top:0;margin-bottom:0"><span style="font-size:
12pt;">Ghadiyali Mohammed Kader,</span></p>
<p style="margin-top:0;margin-bottom:0"><span style="font-size:
12pt;">Research Scholar,</span></p>
<p style="margin-top:0;margin-bottom:0">Dept. of Physics,</p>
<p style="margin-top:0;margin-bottom:0">University of Mumbai.</p>
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<br>
<pre class="moz-signature" cols="72">--
Dr. rer. nat. Thomas Brumme
Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry
Leipzig University
Phillipp-Rosenthal-Strasse 31
04103 Leipzig
Tel: +49 (0)341 97 36456
email: <a class="moz-txt-link-abbreviated" href="mailto:thomas.brumme@uni-leipzig.de">thomas.brumme@uni-leipzig.de</a>
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