[Pw_forum] dynamical matrix

[Alberto Milani]

Dear Eyvaz,
I have already tried changing thr2_ph from 1d-10 to 1d-12 and even more.
Unfortunately, my longitudinal acoustic frequencies are still not good enough 
(the geometry of my system has been carefully optimized and any kind of 
instabilities have been removed). 
Have you any other suggestion?
Thank you very much.
A.M.