The ABINIT Users Mailing List ( CLOSED )

["Dr. Aldo" <aromero@qro.cinvestav.mx>]

Dear abinitiers

I am having some troubles by calculating the phonon structure
of a system under pressure (P=0 is fine). I did the optimization
(using first optcel 0 and then optcel 2) and I did check that the
stresses were correct. I got at that point the right symmetry group (166),
I took out acell, rprim and xred from the optimized file and
include them in the phonon calculation. Then, the symmetry did change
from 166 to 12 and I really do not understand why. If the optimized
values were correct, the phonon calculation should not change the
crystal symmetry, any suggestion?..

For example the optimized values are

acell    7.9899636324E+00  7.9899636380E+00  7.9899636380E+00

rprim    5.7005417696E-01  0.0000000000E+00  8.2160710521E-01
             -2.8502708792E-01  4.9368140048E-01  8.2160710438E-01
             -2.8502708792E-01 -4.9368140048E-01  8.2160710438E-01

xred    2.4055724610E-01  2.4055724610E-01  2.4055724610E-01
             -2.4055724610E-01 -2.4055724610E-01 -2.4055724610E-01


Thanks!!!


regards

-aldo.