[Pw_forum] Problem with Raman and Infrared Active Modes: SOLVED

[Turan Birol]

The Isotropy Software has a module, called SMODES, that does a full
analysis of phonon modes; including their Raman/Infrared activity. It
uses 'simple' group theory only, and the only input it needs is the
structure: Therefore, it cannot be affected by any lack of convergence
or other errors in the DF(P)T calculation. I suggest always using
SMODES -before- doing a phonon calculation to know what to expect.

You can access SMODES at http://stokes.byu.edu/smodes.html

Best,
Turan.


-------
PhD Candidate, Cornell University


On Sat, Dec 3, 2011 at 5:10 AM, Paolo Giannozzi <giannozz at democritos.it> wrote:
>
> On Dec 2, 2011, at 18:32 , HASAN SAHIN wrote:
>
>>      omega(  4 -  5)   =         102.9  [cm-1]   --> E
>> L_3          I+R
>>      omega(  6 -  7)   =         156.9  [cm-1]   --> E
>> L_3          I+R
>>      omega(  8 -  8)   =         402.0  [cm-1]   --> A_1
>> L_1        I+R
>>      omega(  9 - 10)  =         719.8  [cm-1]   --> E
>> L_3          I+R
>>      omega( 11 - 11) =         831.9  [cm-1]   --> A_1  L_1        I+R
>>      omega( 12 - 12) =       1042.2  [cm-1]   --> A_1  L_1        I+R
>
> no inversion symmetry
>
>>      omega(  4 -  5)   =        104.8  [cm-1]   --> E_g
>> L_3          R
>>      omega(  6 -  7)   =        165.5  [cm-1]   --> E_u
>> L_3'         I
>>      omega(  8 -  8)   =        398.5  [cm-1]   --> A_1g L_1         R
>>      omega(  9 - 10)  =        715.3  [cm-1]   --> E_g  L_3          R
>>      omega( 11 - 11) =        827.6  [cm-1]   --> A_2u L_2'        I
>>      omega( 12 - 12) =       1042.5  [cm-1]   --> A_1g L_1        R
>
> inversion symmetry (note the "g" and "u", standing for "gerade", even,
> and "ungerade", odd). In presence of inversion symmetry, Raman-active
> modes are even, Infrared-active modes are odd
>
> P.
> ---
> Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
>
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