[Pw_forum] Symmetry of the dynamical matrix

[Cristian Degli Esposti Boschi]

Dear all,

using the phonon code I noticed that, even
for simple molecular structures, the dynamical
matrix computed by ph.x is not symmetric.
(I limited myself to Gamma point calculations.)

In general, this does not guarantee real
eigenvalues. How are the eigenfrequencies
computed then?

Thanks for your time, Cristian
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Cristian Degli Esposti Boschi
CNR, CNISM, Unita' di Ricerca di Bologna, c/o
Dipartimento di Fisica, Universita' di Bologna
viale Berti-Pichat, 6/2, 40127, Bologna, Italia
tel. ++39 051 2095114   fax ++39 051 2095113
e-mail: cristian.degliesposti -AT- unibo.it
web:    http://www.df.unibo.it/fismat/theory
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