[Pw_forum] Separating Raman modes

[alexandra.carvalho at epfl.ch]

Dear Sophia,

To select which modes are Raman active you must use the selection rules.
The following paper may be of help (see also the tables in it):

Rosseau et al. Journal of Raman Spectroscopy 10, 253 (1981)

If you are starting, I recommend having a look at the selection rules
for molecules, for example in Tinkham, Group theory and Quantum  
mechanics (Dover, 1992,NY) pp248.

Most likelly, you will be interested in the allowed transitions with highest
frequency.

Hope this helps,

Alexandra


Quoting Jonathan <sophia.nishad at gmail.com>:

> Dear users,
>
> I computed phonons only at the gamma point for a 64-atom binary  
> alloy. How do I separate the three main Raman modes.
>
> Would it be possible to get some help?
> thanks,
> --
> Sophia
> UCB, USA
>



-- 

Alexandra Carvalho,
Ceramics Laboratory
Swiss Federal Institute of Technology of Lausanne (EPFL)