The Phonon-GaAs directory
contains the results of frozen Gamma-phonon calculation
(after a precedent relaxation) for a GaAs cell.
The calculated frequencies and eigenvectors are contaied in
GaAs.bands
and
GaAs.vectors

Exercise:

1. using 'vib2xsf', create the .XSF and .AXSF files
for the visualization of phonon modes. Choose a reasonable size
of the visualization cell (noting the latice constant of 5.65 Ang).

2. Verify that the three acoustic modes correspond to the crystal's 
displacement as a whole, and the three (almost degenerate) optical modes 
are a movement of all cations agains the anions.
