[Pw_forum] Fourier interpolation

[giannozz at democritos.it]

Quoting HaoPan <adehaopan at hotmail.com>:

> On each q point I got, the phone frequencies are positive. But after 
> the Fourier interpolation process, There exist negative frequencies.

hard to say what is happening. When you re-generate phonon from
the force constant matrix, you should find exactly the same phonon
frequencies for the wave-vector grid used to generate force constants
in real space. If not, something has gone wrong in the generation
of interatomic force constants

Paolo

----------------------------------------------------------------
This message was sent using IMP, the Internet Messaging Program.