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<p>Dear Suresh,</p>
<p>unfortunately, there is no way to know this before - or at least
I don't know of any.<br>
Yet, you'll nearly always have 3 negative frequencies at the Gamma
point which should actually be zero. Furthermore, it is really
important that you relax your system really carefully before
attempting a phonon calculation - in fact, you should also
decrease the convergence threshold for the scf from the standard
1.D-6 to maybe 1.D-8.</p>
<p>Kind regards</p>
<p>Thomas<br>
</p>
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<div class="moz-cite-prefix">On 29.11.2017 06:24, Suresh A wrote:<br>
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<div>Dear All,<br>
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I am ran phonon calculation for anatase
previously and got negative frequencies. I was install
QE-5.2.0 in serial mode and took days to finish the
calculation in my desktop.<br>
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Is there any way to know the negative frequency before the
calculation ends? So that the time can be saved.<br>
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Thank You <br>
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Yours Sincerly,<br>
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<div style="text-align:right">A.Suresh,<br>
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<div style="text-align:right">Research
Scholar,<br>
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<div style="text-align:right">School
of Physics,<br>
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<div style="text-align:right">Madurai
Kamaraj University,<br>
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<div style="text-align:right">Madurai.<br>
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<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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