CCL:G: Confusing issue of Raman intensity Vs Static polarizability

["Vasile Chis" <vchis]-[phys.ubbcluj.ro>]

Dear Mi Yang,

 

A relationship that can be used for converting calculated Raman activities to  Raman intensities can be found, for instance, in:

P.L. Polavaru, J. Phys. Chem. 94 (1990) 8106

V. Krishnakumar, G. Keresztury, T. Sundius, R. Ramasamy, J. Mol. Struct. 702 (2004) 9.

 

If Freq(Raman) is specified in the route section of Gaussian, Raman activities of normal modes and not Raman intensities are calculated. Raman intensities depend on the exciting laser wave number and on the Boltzmann population of the vibrational levels.

 

Hope this helps!

 

Best regards,

Vasile Chis

=========================
Prof.dr. Vasile Chis                      
Babes-Bolyai University            
Faculty of Physics                  
Kogalniceanu 1  
RO-400084 Cluj-Napoca
Romania    
Tel:  +40264405300  
Fax: +40591906
vchis(a)phys.ubbcluj.ro    
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www.phys.ubbcluj.ro/~vchis
========================

On Thu, Nov 27, 2008 at 11:46 AM, Mi Yang miyang3790*gmail.com <owner-chemistry(a)ccl.net> wrote:

Sent to CCL by: "Mi  Yang" [miyang3790~~gmail.com]
Dear Kzys!!

Yes I am a gaussian03 Rev user but Your comments a bit confusing for me as in G03 manual it is clearly mentioned that by using Freq=Raman you can "Compute Raman intensities in addition to IR intensities" so I am not understanding ur point of view.

http://www.gaussian.com/g_ur/k_freq.htm

There are some good quality of publications where they show computed raman intensities with gaussian e.g.
 J. AM. CHEM. SOC. 2005, 127, 10977-10981.pdf

http://homepage.univie.ac.at/Ferenc.Simon/publications/2005/Schaman_KBproc2005.pdf

So I have stoped my work and first want to confirm it.

Secondly, my calculated Freq value of Raman spectrum is in good agreement  to the experimental value for specific mode of vibrations after scaling. I am not comparing directlt intensity with intensity.My purpose is to show increase of intensity or activity upon intercalation of metal atom.What do you think in this regard?

I need your comments in detail especially in view of above references


> "zborowsk]|[chemia.uj.edu.pl"  wrote:
>
> Sent to CCL by: zborowsk**chemia.uj.edu.pl
>
> >
> > Sent to CCL by: favaro [laurent.favaro[#]u-psud.fr]
> > Do you mean that G03 does not calculate Raman Cross-section ?
> > I believe you are wrong.
>
> Gaussian calculates Raman Activities, not Raman Intensities, and obviously
> it is not the same. Raman Activities cannot be compared directly with
> experimental Raman spectra.
>
> Regards
>
> Kzys
>
> > Regards.
> > LF
> >
> > zborowsk]*[chemia.uj.edu.pl a crit :
> >> Sent to CCL by: zborowsk|,|chemia.uj.edu.pl
> >> Hi
> >> Dear Mi Yang
> >> I want to warn you if you are Gaussian user.
> >> Gaussian does not calculate  Raman Intensities
> >>
> >>
> >>
> >> Sent to CCL by: favaro [laurent.favaro|*|u-psud.fr]
> >>  Raman intensity is related to the square
> >>  of the derivative of polarizability with respect
> >>  to the normal coordinates of the vibrationnal mode.
> >>  Best regards,
> >>  Dr Favaro
> >>  Mi Yang miyang3790_+_gmail.com a crit :
> >>
> >>  Sent to CCL by: "Mi  Yang" [miyang3790*gmail.com]
> >>  Dear CCL users,
> >>  I need some comments or refs about my problem. I am studying the
> >> interaction of a metal with a boron cluster. I found the large increase
> >> of static polarizability and hyperpolarizability upon interaction of
> >> metal atom to that boron cluster. I also calculated the Raman spectrum
> >> which also showed high increase of intensity in metal boron cluster. I
> >> read some indirect relationship b/m these two properties but now in
> >> spite
> >> of my best efforts I could not find the direct relationship between
> >> Static polarizability and Raman intensity. Anybody who knows any ref or
> >> comments about this relationship (Static
> >> polarizability/hyperpolarizability and Raman intensity) would be highly
> >> appreciated.?
> >>  Miyang
> >>  P.R.China>
> >
> >
>
>
> --
> Krzysztof Zborowski
> Faculty of Chemistry
> Jagiellonian University
> 3 Ingardena Street
> 30-060 Krakow
> Poland
> phone: +48(12)632-4888 ext. 2064 or 2067
> fax:  +48(12)634-05-15
> email: zborowsk###chemia.uj.edu.pl
> gg 3817259
> skype kzys70
> www.chemia.uj.edu.pl/~zborowsk
>
>



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