[Pw_forum] Imaginary displacements

[Paolo Giannozzi]

On Nov 19, 2007, at 12:31 , Ion Errea wrote:

> Does anyonone which are the reasons why you can get imaginary
> displacements for phonon eigenmodes?

at q=0 both the dynamical matrix and its eigenvectors are real,
but for a general q, the dynamical matrix is complex hermitian
and its eigenvectors are in general complex

Paolo
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Paolo Giannozzi, Dept of Physics, University of Udine
via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222