Subject: AM1 and PM3

From: "James J. P. Stewart" <[email-masked]>
Date: Wed, 01 Mar 2000 15:42:06 -0700

Although regarded by many as unqualified to offer a review of AM1
and PM3, by reason of presumed bias, I nevertheless feel that some
factual input on this topic would be useful.

For a list of known faults, average errors in heats of formation,
geometries, etc. in MNDO, AM1, and PM3, please look in

http://www.schrodinger.com/Mopac/html/node656.html

or

http://home.att.net/~mopacmanual/node656.html

My objective in writing AM1 and PM3 was to reduce the error in
computed quantities, including hydrogen bonds.  This was partly
successful in AM1 - the geometry of the water dimer was incorrect,
and partly successful in PM3 - the shape of the PES was incorrect.

Jimmy Stewart

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