Thank you very much, Paolo. I see what you said. I'll verify the second part. If I see anything differnt, I'll let you know.
MyTrinh > > On Oct 15, 2009, at 2:16 , vtmtrinh at caltech.edu wrote: > >> I compared the 2 results from the 2 methods, I saw that both ways gave >> the same phonon frequencies, but the displacement vectors are totally >> different. > > no they aren't. Displacement vectors for non-degenerate modes (number 3 > and 6) are the same (within numerical accuracy). For degenerate > modes, you > get different linear combinations (because of the way matrix > diagonalization > works), but the subspace spanned by the two sets of degenerate > eigenvectors > is the same (I haven't verified, but I am sure it is: plase verify) > > P. > --- > Paolo Giannozzi, Dept of Physics, University of Udine > via delle Scienze 208, 33100 Udine, Italy > Phone +39-0432-558216, fax +39-0432-558222 > > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum >
