[Pw_forum] info Raman spectrum

[Tommaso Francese]

Dear all QE users,
i’d like to extrapolate the Raman spectrum of a large supercell ( 96 atoms ) with an aliovalent atom put inside. Being not an expert, i have a little bit confusion on my mind, so i’d like to ask you:

- which kind of pseudopotential  should i use? ultrasoft or norm conserving?;

- pratically, for gaining the Raman spectrum i followed these steps: 
  •relaxed the structure (pw.x);
  •scf of the structure with the new positions (pw.x);
  • ph.x with <lraman> turn on;
  • used dynmat.x for obtaining the frequencies mode.

is it correct? The supercell is made of Zr, O, and 1 atom of Ta. 

I’ll appreciate every suggestion.
Best,
Tommaso Francese,
Università Cà Foscari di Venezia