Chemical Softness by DFT 2

["Jerry C.C. Chan" <chan |-at-| uni-muenster.de>]

 Hi Netters,
 	Last week I posted a question concerning the determination of
 chemical hardness (or softness) of the metal centre of a TM complexes.
 Maybe the way I asked the question was not specific enough, I just
 received two mails asking for the summary.  So I try to write down my
 thinking explicitly and hope that someone in the net, who could not
 tolerate the naiveness or even mistakes of my post, would kindly comment
 on it.  I will summarize.
 I want to determine the chemical hardness of the metal centre of a charged
 TM complexes.  The method that comes to my mind is to do a HF calculation
 and get the MO spectrum.  Based on the Koopmans' theorem the hardness of
 the complexes would be (E_LUMO - E_HOMO)/2.
 Even my thinking is correct, HF calculation seems to be unreliable for TM
 complexes and correlated methods are usually very expensive.  Therefore
 last time I enquired the possibility of using DFT methods as an
 alternative although Koopman's theorem does not hold for KS orbitals.
 By the way, I have heard that Fukui function is somehow related to the
 chemical hardness but I don't have the recipe.
 Many thanks,
 Jerry
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