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[Emmanuel Arras <emmanuel.arras@cea.fr>]

Hi,
I posted this a few weeks ago, and maybe the "knowing" persons weren't there... because I didn't get any answer... So I post it again...
Thanks for your help...


Emmanuel Arras a écrit :

Hi,
 I'm sorry to ask this question since I remember seeing it on the forum, but I can't find it in the archives...

So the question is :
when I compute phonons, for each mode, the atomique displacement vectors' coordinates are given by complexe numbers (in anaddb.out, since my _PHVEC file is empty whatever eivec but that's another problem). I get that the norm of these complexes are the coordinates of the atomique displacement vectors, but I wonder what is the meaning of the complexe phase associated.

Now another question : if I simply take the norm of these complexes and forget about the complexe phase, I get one vector for each atom. Now I get that these vectors should not be the same within the unit cell and a particular mode. But how are these vectors normalized? In other words, what is the meaning of the absolute amplitude of the displacement vectors ?

Thank you

Emmanuel

-- 
Emmanuel ARRAS
L_Sim (Laboratoire de Simulation Atomistique)
SP2M / INAC
CEA Grenoble
tel : 00 33 (0)4 387 86862