Subject: CCL: ZINDO "Heats of formation"

From: "George P. Ford" <[email-masked]>
Date: Thu, 26 Oct 95 18:06 CDT

Joel Polowin writes:

> My calculations with HyperChem for benzoic acid gave heats of formation of
> -68.1 kcal/mol for AM1, -66.4 kcal/mol for PM3, and -3147.6 kcal/mol for
> ZINDO/1.  ZINDO/S did not converge.
> 
> Why are the ZINDO/1 and ZINDO/S methods giving me such apparently
> incorrect values?

I am not a Hyperchem user, but surely the answer is that the ZINDO data are
total energies, not heats of formation at all.

George P. Ford

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George P. Ford                          |      email:  [email-masked]
Department of Chemistry                 |  telephone:  (214)768-2479
Southern Methodist University           |        fax:  (214)768-4089
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