[Pw_forum] frequencies using finite differences instead of perturbation theory?

[Martin Andersson]

Hi,

I am looking into the effects of empirical dispersion, and as far as I 
can see from the phonon output file, the effect from dispersion isn't 
included when the frequencies are calculated using ph.x. Is there a way 
to use finite differences in the QE suite as opposed to perturbation 
theory in order to get frequencies with empirical dispersion included?

Cheers,
Martin Andersson
University of Copenhagen