Subject: Re: CCL:semiempirical PM3 Boron Parameters

From: "Wayne Huang" <[email-masked]>
Date: Tue, 7 Nov 1995 10:03:55 -0800

On Nov 7, 12:04am, Thomas Gray wrote:

> Subject: Re: CCL:semiempirical calculations on a complex of Co and Sn.
> Dear sir,
>
> I have been after boron parameters for PM3 for some time now.  Would you
> please send information or references (or both!) to my address?  I would
> be very interested in running some test calculations of these parameters
> on carboranes and metallacarboranes.
>

Dear Thomas,

Regarding your request for information on PM3 boron parameters, Here are some
initial results.

o Average Error for Geometries:

		   PM3		  AM1
-------------------------------------------
Bond Length	0.037 (146)	0.036 (141)
Bond Angle	3.4 (30)	3.7 (30)

o Average Error for Heat of Formation, Ionization Potential & Dipole Moment:

		PM3		AM1		MNDO
--------------------------------------------------------
HF(71)		10.58		9.43		13.78
IP(26)		 0.41		0.46		 0.98
DM(23)		 0.42		0.32		 0.62

o A series boron compounds where AM1 fails geometrically have been corrected in
this PM3 model.

Both PM3 module (with new parameters for B and soon for Ca) and PM3(tm)
(d-trnasition metals) have built in Spartan software. For further
technical information, please contact [email-masked]

New parameters can be found at:

ftp://ftp.wavefun.com/pub/PARAMS

While the manuscript is in preparation, reference can be cited as:
Yu, J.; Hehre, W. J. To be published, Wavefunction, Inc., Irvine, California
(1995).

--Wayne

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