EIGENVECTORS in OUTCAR ibrion=5,6
Posted: 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.
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.