Subject: Re: CCL:HF/Sadlej calculations

From: "Jens Spanget-Larsen" <[email-masked]>
Date: Fri, 13 Dec 2002 17:19:34 +0100

Henrik Nilsson :

> Has anyone experienced redicolous values of the mulliken charges
> calculated by ab initio quantum mechanical methods with
> HF/Sadlej-pvz basis set? Here is an example and corresponding data
> calculated with HF/6-31G*. The Lowdin charges are similar but the
> mulliken are totally off. 

Mulliken charges depend on the basis set and tend to diverge on 
increasing the number of functions. When diffuse functions are 
included, the Mulliken population analysis may give meaningless 
results. - See f.inst. Frank Jensen's book on computational 
chemistry.

Jens >--< 

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From: Mihaly Mezei <[email-masked]>
Date: Fri, 13 Dec 2002 13:45:51 -0500

> Mulliken charges depend on the basis set and tend to diverge on

A good while ago E. Campbell and myself derived the equations and wrote
the program to partition charge densities by planes placed between pairs
of atoms. The paper (Theoret. Chim. Acta, Vol 43 pp 227-237 (1977) and the
program (MOMENTS) is available at

http://inka.mssm.edu/~mezei/maxwell

Mihaly Mezei,

Dept. of Physiology & Biophysics, Mount Sinai School of Medicine
           Voice: (212) 241-2186     Fax: (212) 860-3369|
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