Subject: Summary: variation of B3LYP parameters

From: "Dale A. Braden" <[email-masked]>
Date: Mon, 5 Jan 1998 12:14:59 -0800 (PST)

Dear CCL,

Many thanks to all who responded to my question about varying the three
parameters in the hybrid DFT functionals:

Original question:

"Does anyone know of any references to studies in which the three
parameters in the B3LYP (or similar) density functionals were varied? 

"Although the optimized parameter values for the B3-hybrids were based
upon fits to experimental data for a set of molecules which did not
contain any transition metals, the B3-hybrids have been used with some
success in modelling transition metal-containing compounds as well. 
However, wouldn't one expect much better results if a new parameter set
for transition metals could be determined?"

In summary, there are no published data yet, although there are at least
two studies about to be published.  Efforts have been mostly directed at
developing entirely new functionals-- see A.D. Becke, J. Chem. Phys. 107
(1997) 8554.  However, the new functionals are optimized for organic
molecules-- no transition metals are in the training set.  Thus, there is
still a need, I think, for developing optimized parameters for transition
metal compounds.  The problem, I suppose, is gathering together
thermochemical data for TM compounds that is as accurate as that for the
G1 and G2 molecule sets.

Best wishes to all,

Dale

Dale Braden
Department of Chemistry
University of Oregon
Eugene, OR 97403-1253
[email-masked]