Subject: Summary: AIM analysis & ECP basis set

From: "Dr.Tapan K.Ghanty" <[email-masked]>
Date: Mon, 22 Jan 2001 14:06:01 +0530 (IST)

Hi,

Here is my query followed by the replies I got for this.

Thanks for the useful replies.

Tapan

On Tue, 9 Jan 2001, Dr.Tapan K.Ghanty wrote:

> Hi All,
> 
> I was wondering whether Bader's Atom-in-Molecule (AIM) analysis
> can be performed (in-principle as well as in-practice) on a 
> wavefunction which is calculated using ECP basis sets.
> 
> With thanks,
> 
> Tapan K. Ghanty

REPLIES:
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# 1
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From: Frederick P. Arnold Jr. <[email-masked]>

Sort of.   You need to look up some papers by Gernot Frenking from around
1995 on this topic.  The shortcomings basically are that because of the
lack of core density, (1) spurious critical points appear in the molecular
graph, (2) residual density in the core region caused by the s-orbitals
causes numerical instabilities in various search routines, and (3) the
first two make it difficult to reliably integrate the density, especially
in regions of complex topology.

You're probably better off doing everything up to the AIM analysis with
ECP, and then using the basis sets in the Huzinaga green book
(appropriately split and augmented) for a single-point calculation to
generate the wfn file.

						-fred

					Frederick P. Arnold, Jr.
					NUIT, Northwestern U.
					[email-masked]

# 2
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From: "Shobe, Dave" <[email-masked]>

My understanding is that it can be done, IF one fills in the missing
electron density.  I've seen a paper somewhere where this was done, i.e. a
fixed core density was added to the electron density from the calculation.
I don't remember how they got the core density though, or anything helpful
regarding tracking down the paper.  :-(  

("I don't remember the author or title, but I think the book was red.")