CCL: Experimental Raman and IR not matching with theory

[partha kundu <partha1kundu : gmail.com>]

Dear Kalyan,

Thank you for your suggestion. Actually I am trying to simulate some experimental results which is not published. Could you send me any paper where authors has followed similar approach. It will be easier for me to understand then. One question I have, will taking water not affect the position and intensity of vibrational bands, some references will help me for supporting the approach.

Thanks and kind regards.

Partha.

On Sun, Aug 25, 2013 at 3:57 PM, kalyan onekalyan,yahoo.com <owner-chemistry##ccl.net> wrote:

Could you please send me the experimental paper ? Eventually try to do rum your calculation in g09 smd model with 6-31+g(d,p) set. And run cation only both gas and water as well as run anion too. You can get Reaction energy as well as  binding energy. So it will be your supporting information. 

Best Regards
Kalyan

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From: partha kundu partha1kundu{}gmail.com

Sent: 25/08/2013 12:15
To: Dhar, Kalyan kumar

Subject: CCL: Experimental Raman and IR not matching with theory

Dear Kalyan,

Thanks for your answer. So what solvent do you think would be better to simulate solid phase?

regards.

Partha P. Kundu
PhD student
Light Scattering Laboratory
Chemistry & Physics of Materials Unit
Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bangalore,  560064 INDIA
Phone +91 80 2208 2811/2853 (Lab)

On Sun, Aug 25, 2013 at 1:16 PM, kalyan onekalyan^^^yahoo.com <owner-chemistry^-^ccl.net> wrote:

Probably since I am doing the calculation in gas phase adding BPh4- close to Na+ causing the Na to go little distant from catalyst and shift in catalyst frequency is diminished.

_________________________________________________________________________-

How come you will run your calculation for a complex in gas phase .? 

Molecule in gas phase did first then run its in liquid phase . then their is a meaning . But only gas phase is meaningless or no sense 

Best regards

kalyan . 

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From: partha kundu partha1kundu[]gmail.com <owner-chemistry%x%ccl.net>
To: "Dhar, Kalyan kumar " <kalyan.dhar%x%mail.polimi.it>
Sent: Sunday, August 25, 2013 8:21 AM
Subject: CCL: Experimental Raman and IR not matching with theory

Dear All,

I am trying to simulate IR and Raman of a catalyst and trying to see the effect of Na+ on the frequency. For catalyst I am getting very good match for Raman (after converting to intensity), but for IR some strong experimentally observed modes (like S=O str.) are appearing as medium or weak band in theory. I am taking a dimer (obtained from crystal structure and then optimized) in gas phase to simulate the solid. I know IR intensity strongly depends upon intermolecular interaction which is not described properly by taking dimer. How to match the intensity better?
Then I tried to add Na+ cation to the catalyst to see the shift in frequency. Shift in frequency is qualitatively changing as observed in experiment. Now I want to add a counter ion (BPh4), to get the contribution from it as seen in experiment. Probably since I am doing the calculation in gas phase adding BPh4- close to Na+ causing the Na to go little distant from catalyst and shift in catalyst frequency is diminished. The crystal structure of the complex is not known, so I do not have any idea of where to add it. I do see interaction of BPh4 with the catalyst, 4 Phenyl ring breathing mode is split in the complex. Could you suggest how to solve the problem?
Thanks and regards.
Partha