check your algebra text-book. An hermitian matrix has real eigenvalues and in general complex eigenvectors. If you are surprised think of simple example where you KNOW the answer... For instance free electrons: the hamiltonian is real, the eigenvalues are real... the eigenvectors are plane-waves (i.e. complex funcions) Stefano de Gironcoli
Ion Errea wrote: > Dear all, > > Does anyonone which are the reasons why you can get imaginary > displacements for phonon eigenmodes? As far as I remember from algebra, > the dynamical matrix is real and symmetric, thus hermitian, and > hermitian matrices have real eigenvectors and eigenvalues. Therefore I > don understand why I get this results. Problems with convergence maybe? > > Thanks for your answers, > > Ion > > ==================================================================== > Ion Errea Lope > Department of Condensed Matter, Unibersity of the Basque Country > Apdo. 644 > 48080 Bilbao (Spain) > Tlf: +34 94 601 5322 > > > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum >
