Subject: Chemical Softness by DFT 2

From: "Jerry C.C. Chan" <[email-masked]>
Date: Fri, 9 May 1997 15:42:13 +0200 (MES)

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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