Subject: Multideterminantal DFT

From: "Jan H. Jensen" <[email-masked]>
Date: Thu, 3 Sep 1998 17:23:37 -0500

The possible need for multideterminantal DFT has been most interesting
and seems to me to be of fundamental importance.  I would like to add
my (current) view on this and get other people's opinions on it.  

	In so far as the exchange-correlation functional used is correct, the
main consideration should be whether the density from a single
determinant wavefunction can accurately describe the exact density. 
Handy has discussed this issue for a two-electron case (J.Chem.Phys.
105, 9202, 1996) and states that only within an infinite basis set is
that rigorously possible.  Thus, the need for several configurations in
DFT calculations is likely to be very basis set dependent.  Depending
on the rate of basis set convergence (and the form of the empirical
functional?), it may be more computationally efficient to include a few
more determinants to get a better description of the density.  However,
>from a purely formalistic point of view (exact functional, infinite
basis set) one determinant should be sufficient for any system.

	Best regards, Jan Jensen

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Jan H. Jensen				Assistant Professor

Department of Chemistry			[email-masked]

University of Iowa			Phone:(319) 335-1108

Iowa City, IA 52242			FAX:  (319) 335-1270

http://www.uiowa.edu/~chemdept/faculty/jensen/

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