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<div class="moz-cite-prefix">the dielectric constant computed by
phonon is the static (high-frequency) dielectric constant of the
system (also referred as \epsilon_\infty in the literature). One
need to combine it with phonon results in order to compute
\epsilon_0, the real static dielectric constant including also
ionic polarization. It is a GS property and its computation is
exact (as much or as little as your xc functional is <span
class="moz-smiley-s1"><span> :-) </span></span>).<br>
<br>
As for epsilon... the code says<br>
! Compute the complex macroscopic dielectric function,<br>
! at the RPA level, neglecting local field effects.<br>
! Eps is computed both on the real or immaginary axis<br>
!<br>
so RPA (i.e. no xc contributions to the response), no local fields
(i.e. only diagonal screening) but frequency dependence<br>
<br>
computed from an explicit summation of dipole matrix elements and
transition energies. <br>
<br>
stefano <br>
<br>
On 11/08/2015 11:24, Khalid Ibne Masood Khalid wrote:<br>
</div>
<blockquote
cite="mid:CALoavpYf0hhBb2aTFNPLpj4UYUR8Pn4ia9=7CduwRdrTON_sTA@mail.gmail.com"
type="cite">
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<div>Dear Researchers,<br>
</div>
I apologize that this might not be related to the code,
but it would be very kind of you to help me in this
regard. I was wondering what is the difference between
the dielectric constant calculated from epsilon.x and
the dielectric constant calculated from ph.x ? Is it
like that epsilon.x calculates the dielectric constant
due to electrons alone? I would also appreciate if you
could suggest some basic references regarding epsilon.x<br>
<br>
</div>
Thank you.<br>
<br>
</div>
Khalid<br>
</div>
M.Sc student<br>
</div>
BUET <br>
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