ABINIT Discussion Forums

finally I came to the conclusion that this concept is not applicable in case of imaginary frequencies. I hoped that there was a solution implemented in anaddb but to my knowledge there's no way to calculate the free energy with unstable phonons within the harmonic approximation since these imaginary...

Hi, I'm interested in how anaddb deals with imaginary phonon frequencies to calculate the phonon free energy because \[ F_vib = k_BT int_0^{\infty} ln {2 sinh [\frac {\hbar \omega}{2k_B T}]} g (\omega) d \omega \] can only be used for real frequencies. How can one take imaginary frequencies into acc...