[Pw_forum] Negative phonon frequencies?

[Lu Frederic]

Dear PWscf users,

While calculating phonon frequencies at Gamma of zb/wz GaN using
PWscf_v1.2.0,
no matter what Ga 3d core electrons treat as valence electrons. I am always
found
negative frequencies in the output file.

I guess that I am not the first people to ask why? but I don't know how to
search
old Pw_forum digest. If someone really know what's volume and number have
talk about negative phonon frequencies, please tell me.

Thank you

Lu Fu-Fa, 10/02/2003