[Pw_forum] orthogonality of phonon eigenvectors?

Paolo Giannozzi giannozz at democritos.it
Fri Feb 10 14:07:10 CET 2012

On Feb 10, 2012, at 24:32 , Suza W wrote:

>    For example, after the above algebra, we get, these well- 
> arranged eigen displacements
> [...]
> ,whereas the initial eigen-vectors that QE code prints directly  
> (which is indeed messy)

if you have degenerate eigenvalues, any linear combination of  
in the degenerate subspace is a solution. What you get from numerical
diagonalization depends upon the phase of the moon.

Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222

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