Subject: Modeling Electrostatics

From: Marcus G Martin <[email-masked]>
Date: Thu, 30 Jan 1997 11:17:35 -0600 (CST)

On Thu, 30 Jan 1997, Dr. Heinz Schiffer wrote:

-SNIP-
> Hi,
> why does no one uses ( or is even aware of ) the population analysis
> method of Davidson, Roby, and Ahlrichs ? In my opinion, it is the
> cheapest one ( compared to Bader or NBO ) with the highest
> interpretation potential ( no one should use population charges
> to model the electrostatic potential of a molecule. These are quiet
> different things !!! ). Here are the references :
-SNIP-

What should I do if I want to fit the electrostatic potential of a 
molecule?  I have been fitting lennard-jones 12-6 force fields to alkanes 
and would like to move into the (frightening) world of slightly charged 
molecules.  Nothing extremely painful, such as water, but more like 
alkanols or carboxillic acids.  
	The running discussion on charges appears to me to say that the 
charges computed from quantum mechanics are of little use for fitting a 
force field.  I would like to know if the computational community has a 
feel for what the 'best' and most efficient way of fitting point charges 
to these molecules would be.
thanks, I will summarize the responses if there is interest.

Marcus Martin             Graduate Student
Department of Chemistry,  University of Minnesota
[email-masked]  http://siepmann6.chem.umn.edu/~marcus