[Pw_forum] Separation between acoustic modes and optical modes

[Umesh Roy]

Dear All,
           I have calculated modes of vibration of Iron in different
directions for a fix phonon wave vector q (in a large number of
directions). Since in Quantum espresso phonon modes are printed in
increasing order for a given q vector. For a small group of q the acoustic
and optical branches do not overlap so, we can easily separate out the
acoustic branch from the optical branch. As we increase the magnitude of q
the acoustic branch and the optical branch get mixed up. So , how to
separate out the acoustic modes or is there any way of filtering the
optical modes?


Thank you in advance





*Umesh Chandra RoyResearch Scholar, School of Physical SciencesJawaharlal
Nehru University, New Delhi-110067,*

*India.*

*Email:umesh24crp at gmail.com <Email%3Aumesh24crp at gmail.com>*
*Mobile:+919868022722*
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