[Pw_forum] Raman and IR intensities for a metal

[Stefano Baroni]

Dear Miriam: you and others will forgive my ignorance, but I would  
need some further explanations. According to the usual theory, they  
both should be zero:````````````````````` the second is given by Born  
effective charges (that are zero in metals), the former by the  
derivative of the inverse macroscopic electric constant (which is also  
zero). How can a metal be Raman or IR active? Thanks - SB

On Dec 14, 2007, at 7:18 PM, Miriam Marques wrote:

>  Dear ESPRESSO users,
>
>  I would like to know if it is possible to compute
>  Raman and Infrared intensities for a metallic system.
>
>  Thank you very much in advance,
>
>  Miriam.
>
>  Dr. Miriam Marques
>  Centre for Science at Extreme Conditions.
>  The University of Edinburgh.
>  e-mail: mmarques at staffmail.ed.ac.uk
>
>
> -- 
> The University of Edinburgh is a charitable body, registered in
> Scotland, with registration number SC005336.
>
>
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---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
Trieste
[+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)

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