[Pw_forum] phonon modes assignment and others

[W. YU]

Thanks to Axel, Paolo and other pw members for
answering my quesitons on the Alkali pseudopotentials.
I have just checked this forum and found the new
answers. I will be back to this question later when I
have my results available next Monday. 

Now I have some other quesitons concerning the phonon
calculations and the symmetry modes assignment:

1. Is there an easy or not so easy way to assign the
different modes from the phonon calculation results to
the various irreducible representations? From the
correlation between site and factor groups, some
information about which atom contributes to which
irreducible representation or not can be found as well
as some polarizibility characters. Any better way to
do this job?

2. When I use dynmat.x to extract normal mode eigen
vectors for the Gamma point, the results seems to be
different from those given by the phonon output.
What's the difference between the eigen vectors
printed out by dynmat.x and Phonon codes (if there
are, besides the dropping of phase factors in the
dynmat.x output)?

3. When doing phonon calculation, we are not using
supercell, but I know q2r does account for the
interactions among different neighbours. Then is it
possible for me to know exactly up to which nearest
neighbour is included in the calculation?

Sorry for too many quesitons, I just hope to make it a
whole.

Best regards,

W. YU


		
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