Subject: Re: CCL:M:(URGENT)HELP!: Serious error in MOPAC93-looking for solution

From: Karl Irikura <[email-masked]>
Date: Tue, 06 Aug 1996 11:55:09 -0400

Try empirical estimation methods.  Some are described in Lias, S. G.;
Bartmess, J. E.; Liebman, J. F.; Holmes, J. L.; Levin, R. D.; Mallard, W. G.
J. Phys. Chem. Ref. Data 1988, 17, Suppl. 1. "Gas-Phase Ion and Neutral
Thermochemistry." 

See in particular section 2.5 ("Trends in the Data") and subsection 2.5.1
("Estimation Schemes for Heats of Formation of Cations").  Section 4.4
("Estimated Heats of Formation") may also be helpful.  

The book can at least provide several leads.

Good luck!

Karl Irikura

>Is it really true that MOPAC93 is not accurate enough fo delta_Hf
>calculation?  If so, what else do I have to try ?  Is there any other 
>way in the field of computational chemistry which can produce the 
>value of delta_Hf data as correct as possible for various gas-phase 
>carbenium ions??
>
>ANY suggestion/advice/information will be GREATLY appreaciated.
>
>Thanks in advance.
>
>
>				Sincerely,
>
>				     Park, TAE-YUN    
>=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>State University of Ghent
>Laboratorium voor Petrochemische Techniek
>Krijgslaan 281, Blok S5  
>9000 Gent, Belgium	  
>TEL:+(32)-0(9)-264-4527
>FAX:+(32)-0(9)-264-4999
>e-mail: [email-masked]
>=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>
----------------------------------------------
Dr. Karl K. Irikura
Physical and Chemical Properties Division
National Institute of Standards and Technology
Gaithersburg, MD  20899
voice: 301-975-2510	fax: 301-975-3670
e-mail: [email-masked]
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