Subject: CCL: Time-Dependent-DFT Oscillator Strengths

From: "Jens Spanget-Larsen" <[email-masked]>
Date: Wed, 4 Aug 1999 16:33:46 +0100

CCL:

TD-DFT theory appears to provide a useful approach to the electronic 
spectra of many molecules.  In our lab, TD-B3LYP calculations 
(Gaussian98w, vs. 5.0) have satisfactorily reproduced transition 
energies and relative intensities for several organic chromophores.  
However, the absolute intensities are much too low: The predicted 
oscillator strengths are one order of magnitude too small, compared 
with data derived from experimental spectra.  The discrepancy does 
not seem to depend significantly on basisset.

Is this a problem intrinsic to TD-DFT?  What is the 
explanation?

Thank you, Jens >--< 
                             
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JENS SPANGET-LARSEN         Phone:  +45 4674 2000  (RUC)
Department of Chemistry             +45 4674 2710  (direct)
Roskilde University (RUC)   Fax:    +45 4674 3011 
P.O.Box 260                 E-Mail: [email-masked]
DK-4000 Roskilde, Denmark   http://www.rub.ruc.dk/dis/chem/psos/
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