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<div class="moz-cite-prefix">if the calculation is properly
converged an imaginary frequency (printed as negative in the
output) signals a structural instability for atoms moving
according to the vibrational pattern.<br>
<br>
To find the new structure look for a supercell for which the given
q-vector would be folded in Gamma, slightly displace the atoms
according to the unstable vibrational pattern and relax.<br>
<br>
stefano<br>
<br>
<br>
On 06/04/2015 17:31, Masoud Avi wrote:<br>
</div>
<blockquote
cite="mid:CAC4vesHjfRwRMONMsQ97rZrrQND+DpmdTPW9ZF1TrL4udEQHmg@mail.gmail.com"
type="cite">
<div dir="ltr">Hi
<div>I've calculated the phonon distribution, But at a point
other than the gama point is negative frequency !! </div>
<div>What is the reason? and What to do?</div>
<div>thanks</div>
</div>
<br>
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