How about decomposing eigenstates into that for the
individual atoms and summing them for each species, since the phonon
frequencies are computed already, and the eigenmodes for each
frequency are known. By analyzing these quantities
graphically for each species, optical frequencies of the main three
modes could be detected, I think. <br>
<br>Zubaer<br>Department of Mechanical Science and Engineering<br>Univ. of Illinois at Urbana-Champaign, USA<br><br><div class="gmail_quote">On Tue, Jun 23, 2009 at 11:14 AM, Paolo Giannozzi <span dir="ltr"><<a href="mailto:giannozz@democritos.it">giannozz@democritos.it</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class="im">Stefano Baroni wrote:<br>
<br>
> The method by Mauri and coworkers<br>
> (whose implementation status in QE is unknown to me)<br>
<br>
</div>it is implemented, but only for the "ordinary" phonon<br>
code (i.e. not for the Gamma-specific one) and only for<br>
norm-conserving pseudopotentials<br>
<br>
Paolo<br>
<font color="#888888">--<br>
Paolo Giannozzi, Democritos and University of Udine, Italy<br>
</font><div><div></div><div class="h5">_______________________________________________<br>
Pw_forum mailing list<br>
<a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>
<a href="http://www.democritos.it/mailman/listinfo/pw_forum" target="_blank">http://www.democritos.it/mailman/listinfo/pw_forum</a><br>
</div></div></blockquote></div><br>