[Pw_forum] Vibration Spectrum from QE

[Paolo Giannozzi]

Eyvaz Isaev wrote:

> Please have a look at example06 in /examples.
> Of course, you should use a supercell, calculate
> phonons and then projected phonon dos. 
> If you mean to calculate vibrations of selected atoms
> I think you can try "nat_todo" keyword for phonons,
> but not sure it will work in your particular case, 
> as this keyword has been used for a special structure
> (fullerene, if I remember correctly from Paolo's
> reply).

no, 'nat_todo' is used to select a subset of atoms for
which to perform the linera response calculation. For
instance, if you have a molecule on a surface, you may
calculate the dynamical matrix for the atoms in the
molecule only, if you want. The specialized code "phcg.x"
(example in examples/example09) was originally written
for fullerenes and molecules: it uses k=0 sampling only,
calculates phonons at q=0 only

Paolo
-- 
Paolo Giannozzi, Democritos and University of Udine, Italy