RM1: a Reparameterization of AM1 for H, C, N, O, P, S, F, Cl, Br, and I

Gerd Bruno Rocha, Ricardo Oliveira Freire, Alfredo Mayall Simas*, and James J. P. Stewart.
Journal of Computational Chemistry 27(10), 1101-1111, 2006

• RM1 is a fully disclosed, and public domain semiempirical molecular orbital model.


• Capable of modeling most molecular systems of importance to organic chemistry, biochemistry and pharmaceutical research;


• Essentially identical to the AM1 method, but with improved performance - with much newer and better parameters.


• A known error in PM3 nitrogen charges is corrected in RM1.


• In most cases, RM1 yields superior results to both AM1 and PM3 - for organic and biomolecules.


• RM1 is different from PM5 and PM6, which use dissimilar equations, mainly affecting the way the core-core interaction is defined.

RM1 (Recife Model 1) was named in recognition of the city of Recife, where the model was developed.