[Pw_forum] phonon branch crossing problem

[W. YU]

Thank you stefano for answering my questions.

Now I have a question about the crossing of the phonon
branches. I know there are some rules govening the
phonon branch crossing such as branches belonging to
the same irrep will not cross each other. I don't know
how PHONON manages this problem. I have never seen any
crossing(in the sense of my understanding) of the
dispersion curves calculated by PHONON, only tangent
touching. But some of the experimental results did
indicate crossing of the curves. Could anyone give
some comments on this?  Thanks!

W. YU


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