From owner-chemistry@ccl.net Mon May 25 11:16:01 2009 From: "David Gallagher gallagher.da::gmail.com" To: CCL Subject: CCL:G: Experimental and theratical UV calculation Message-Id: <-39370-090525111248-18831-AM0UO36eQGtpRkR9CD3Aog+/-server.ccl.net> X-Original-From: David Gallagher Content-Type: multipart/alternative; boundary="=====================_11280046==.ALT" Date: Mon, 25 May 2009 08:12:19 -0700 Mime-Version: 1.0 Sent to CCL by: David Gallagher [gallagher.da-x-gmail.com] --=====================_11280046==.ALT Content-Type: text/plain; charset="us-ascii"; format=flowed Hi Saurabh, There are various issues that can explain possible discrepancies between experimental and theoretical UV spectra, including geometry, solvation and vibrational fine structure, etc. The key issues are discussed and illustrated in a slide presentation posted at http://cacheresearch.com/presentations.html (top of page). I hope this helps. Regards, David Gallagher CACheResearch.com At 10:57 AM 5/23/2009, Saurabh Agrawal Saurabh.Agrawal!A!ucdconnect.ie wrote: >Hello, > >I have calculated UV absorption spectrum for some molecules using >Gaussian. With the following basis set and cards. > >#p B3LYP/6-31g** TD(Singlet,NSTATES=15) guess=read geom=check > >The results I got are considerably different from experimental results. > >1) Can we compare the theoretical results with experimental results? >I appreciate if some one could send link for some basic notes on it. > >Sincere regards, > >Saurabh > > > >Saurabh Agrawal, >PhD Student, >Department of Chemical and Bioprocess Engineering, >UCD, Belfield, >Dublin-4, Ireland --=====================_11280046==.ALT Content-Type: text/html; charset="us-ascii" Hi Saurabh,

There are various issues that can explain possible discrepancies between experimental and theoretical UV spectra, including geometry, solvation and vibrational fine structure, etc.  The key issues are discussed and illustrated in a slide presentation posted at http://cacheresearch.com/presentations.html (top of page).

I hope this helps.
Regards,
David Gallagher
CACheResearch.com


At 10:57 AM 5/23/2009, Saurabh Agrawal Saurabh.Agrawal!A!ucdconnect.ie wrote:
Hello,

I have calculated UV absorption spectrum for some molecules using Gaussian. With the following basis set and cards.

#p B3LYP/6-31g** TD(Singlet,NSTATES=15) guess=read geom=check

The results I got are considerably different from experimental results.

1) Can we compare the theoretical results with experimental results? I appreciate if some one could send link for some basic notes on it.

Sincere regards,

Saurabh



Saurabh Agrawal,
PhD Student,
Department of Chemical and Bioprocess Engineering,
UCD, Belfield,
Dublin-4, Ireland
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