[Pw_forum] Imaginary displacements

[Ion Errea]

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

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Ion Errea Lope
Department of Condensed Matter, Unibersity of the Basque Country
Apdo. 644
48080 Bilbao (Spain)
Tlf: +34 94 601 5322