EIGENVECTORS in OUTCAR ibrion=5,6

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ietxeba
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EIGENVECTORS in OUTCAR ibrion=5,6

#1 Post by ietxeba » Mon Dec 09, 2019 2:10 pm

Dear all:

VASP documentation clearly states that eigenvectors of the dynamical matrix are witten in the OUTCAR in DIRECT (i.e. Fractional) format.

wiki/index.php/Phonons_from_finite_differences

"The following column is the label for the atomic positions in Cartesian coordinates (x,y,z) and the normalized eigenvectors of the eigenmodes in direct coordinates."

I ask this because I have repeated a particular phonon calculation using phonopy (and VASP as a Force calculator) and VASP (ibrion=5). It turns out that although the obtained "e" eigenvectors are identical, atomic displacements defined as: e/sqrt(N*amu) do not agree. Or more exactly, what phonopy's output writes as cartesian, it shold be direct in VASP.
So, I would only want to confirm, that in the OUTCAR what is written in the documentation is correct, i.e., eigenvectors are in direct.

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