On Wed, Mar 1, 2017 at 1:22 PM, Azadi, Sam <[email protected]> wrote:
> 3N normal coordinates related to 3*N normal modes are displaced compared to > relaxed positions, if I’m right. Nothing is actually "displaced": what is computed is the linear response to a given displacement pattern, using perturbation theory. The amplitude of the perturbation does not affect the calculation. Specific displacement patterns depend upon the symmetry of the (unperturbed) crystal and are chosen along irreducible representations of the symmetry group. I think they are normalized but I don't remember exacty how. Paolo -- Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222 _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
