Subject: Re: CCL:semi-empirical methods (fwd)

From: Estiu Guillermina <[email-masked]>
Date: Fri, 27 Oct 1995 09:36:49 -0300 (EST)

---------- Forwarded message ----------
Date: Fri, 27 Oct 1995 06:30:44 -0500
From: Mike Zerner <[email-masked]>
To: [email-masked]
Subject: Re: CCL:semi-empirical methods (fwd)

Hi Guillermina,

INDO/S cannot be used for heats of formation.  It gives energy differences
between ground and excited states for a fixed geometry, much like a 
propagator calculation would give.  There is no nuclear repulsion given
here, as it does not change in the ground and excited state at a fixed
geometry, as one example.

INDO/1 is capable of giving heats of formation, but the energy of the
reference atoms under INDO/1 must be calibrated and subtracted
>from the molecular calculation.   This is something I once looked at
and it does work. But the only energy my ZINDO prints out is the total
energy, not the heat of formation.  Perhaps Hyperchem has done this, but
judging from the numbers I doubt it.  If this is done correctly
heats of formation are usuually somewhat to low (overbound).

All the best,   Mike Z.
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you might wish to forward this to the appropriate people!