[Pw_forum] Third order anharmonic dynamical matrix

[Jonathan Breeze]

Dear Pwscf Users,

Thanks Paolo for the archive containing examples on how to calculate the
third order anharmonic coefficients.
Everything worked fine for Beryllium and I have managed to calculate the D3
coefficients for a few other metals like Aluminium and Iron.
I have now been trying to calculate for insulators but get very small
numbers for the TO phonon which don't agree with the numerical calculation.
I was wondering if there was a problem with calculating for insulators with
wide band-gaps.

Kinds regards,

Jonathan Breeze