[Pw_forum] Phonon frequency

[Axel Kohlmeyer]

On Sun, Apr 8, 2012 at 12:17 PM, henry odhiambo <henod2001 at yahoo.com> wrote:

> Hello colleagues,
>
> I am calculating the phonon frequencies for stable ( or hexagonal) GST
> (Ge2Sb2Te5). I am getting some negative values (contrary to the notion of
> stability and literature). I used the unrelaxed structure to do the
> calculations. Could this be the reason?
>

yes. check out how phonons are calculated
and then it will be evident why.

axel.



>
> Henry Otunga
> Dept. of Physics
> Maseno UNiversity
> Kenya
>
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>


-- 
Dr. Axel Kohlmeyer
akohlmey at gmail.com  http://goo.gl/1wk0

College of Science and Technology
Temple University, Philadelphia PA, USA.
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