Subject: Summary on oscillator strengths in TD-DFT.

From: pascal boulet <[email-masked]>
Date: Mon, 28 Feb 2000 15:55:07 +0100

Dear CCL'ers,

Few weeks ago I send a question concerning the reliability of oscillator
strengths in TD-DFT. Here is the answer I get (thank you Prof. Stefan
Grimme):

Dear Pascal,
to my knowledge there is no systematic investigation
on f-values with TDDFT. This makes sense because
the systems for which TDDFT is usually used are quite large
so that accurate exp. or theor. f-values are difficult
to obtain. From my experience it turned out that the TDDFT f-values
are quite reliable if the state is reasonably described by the
method. They are usually better than those from CIS
(because the RPA type equations solved satisfy certain sum rules)
and may also be better than those from RPA (because the KS-orbitals
are better). Care should be taken if states with diffuse(Rydberg)
character are considered. A (however not too meaningfull) hint
on the accuracy can be obtained by comparison of f(L) and f(V)
(should be identical in a complete basis).

Stefan

___________________________________________
       Prof. Dr. Stefan Grimme
    Organisch-Chemisches Institut
     (Abt. Theoretische Chemie)
  Westfaelische Wilhelms-Universitaet
         Corrensstrasse 40
         D-48149 Muenster
     Tel (+49)-251-83 36512/33241
     Fax (+49)-251-83 36515
     Email:[email-masked]
___________________________________________

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Pascal BOULET               [email-masked]
Département de Chimie-Physique
Université de Genève
30, Quai Ernest-Ansermet
CH-1211 Genève 4
tel: (+41) 22 702 65 77 or (+41)  22  702 65 32
fax: (+41) 22 702 65 18
and
Université Claude Bernard Lyon 1
 43, Bd du 11 Novembre 1918
69622 Villeurbanne Cedex               France
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