[Pw_forum] Problem with Raman and Infrared Active Modes

[Martin Andersson]

In C3v symmetry the A1 and E modes are both IR and Raman active. The A2 
modes are inactive in both techniques. See e.g.

http://www.webqc.org/printable-symmetrypointgroup-ct-c3v.html

x,y,z are IR active, and x2+y2,xy,etc are Raman active

Cheers,
Martin Andersson,
university of Copenhagen

On 10/7/2011 3:35 PM, Paolo Giannozzi wrote:
> On Fri, 2011-10-07 at 15:54 +0300, HASAN SAHIN wrote:
>
>> According to this, my system has a symmetry.
> it has no inversion symmetry. If I remember correctly, in systems
> having inversion symmetry, modes are either IR- or Raman-active
> but not both. Do you have any evidence that some of the modes
> indicated as active are not?
>
> P.