Subject: Re: CCL:van der Waals radius

From: Per-Ola Norrby <[email-masked]>
Date: Tue, 20 May 1997 07:59:55 +0200

Shridhar Gadre wrote:
>Dear Sirs : Could someone give us van der Waals radius for
>Lithium, Boron , Chlorine, Fluorine and Oxygen atoms? Thanks.
>(We do have radii of some elements from this list..we will
>check consistency with your values)......Shridhar Gadre

	Dear Dr. Gadre,

	The vdW radius is not a perfectly well-defined quantity, it depends
on the context in which you are using it.  I assume that you want it for
use in a force field program of some kind, then it depends on the
functional form utilized by the force field in question.  Allinger et al.
published values suitable for MM2 and MM3, for the entire periodic table,
in J.Mol.Struct. (Theochem) 312 (1994) 69-83.  Note that none of these use
a Lennard-Jones-potential, if you want numbers suitable for that functional
form, you should go to other sources.

			 MM2	 MM3
	Lithium		2.38	2.55
	Boron		1.98	2.15
	Chlorine	2.03	2.07
	Fluorine	1.65	1.71
	Oxygen		1.74	1.82

	Sincerely,

	Per-Ola Norrby

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 *  Per-Ola Norrby, Associate Professor
 *  The Royal Danish School of Pharmacy, Dept. of Med. Chem.
 *  Universitetsparken 2, DK 2100 Copenhagen, Denmark
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