The ABINIT Users Mailing List ( CLOSED )

[Javier Torres <javier.torres@unito.it>]

Dear Yunhee

The message that you obtain during the rf calculation is a consequence 
of a incomplete dynamical matrix... A complete dynamical matrix is 
generated considering the displacement of all the irreducible atoms in 
your unit cell in the three cell directions...
Ex:
If you have 6 atoms in your unit cell you have to define

rfphon 1
rfatpol  1 6      # it means from atom 1 to atom 6
rfdir      1 1 1   # it means displacements along a, b and c directions

If your have atoms related by symmetry the calculation is performed only 
for the irreducible set of atoms and directions, th ematrix then is 
completed considering symmetry...

The message, that you observe, is displayed when you calculate the 
phonon frequencies considering only some atoms or one direction; 
therefore ABINIT tell you that the obtined phonons may be wrong... 
Anyway often these incomplete dynamical matrices can be merged (using 
MRGDDB) in some cases in order to get a bigger matrix that can be 
analyzed with ANADDB...

Best Regards

F. Torres