EIGENVECTORS in OUTCAR ibrion=5,6

Queries about input and output files, running specific calculations, etc.


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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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Re: EIGENVECTORS in OUTCAR ibrion=5,6

#2 Post by support_vasp » Wed Sep 11, 2024 3:06 pm

Hi,

We're sorry that we didn’t answer your question. This does not live up to the quality of support that we aim to provide. The team has since expanded. If we can still help with your problem, please ask again in a new post, linking to this one, and we will answer as quickly as possible.

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