AM1 was developed by Michael Dewar and co-workers and published in 1985. AM1 is an attempt to improve the MNDO model by reducing the repulsion of atoms at close separation distances. The atomic core-atomic core terms in the MNDO equations were modified through the addition of off-center attractive and repulsive Gaussian functions.
The complexity of the parameterization problem increased in AM1 as the number of parameters per atom increased from 7 in MNDO to 13-16 per atom in AM1.
The results of AM1 calculations are sometimes used as the starting points for parameterizations of forcefields in molecular modelling.
Dewar, M. J. S., Zoebisch, E. G., Healy, E. F. and Stewart, J. J. P., Journal of the American Chemical Society, 107, 3902, (1985).
Dewar, M. J. S., Jie, C., Yu. J., Tetrahedron, 49, 5003, (1993).
Freire, R. O., Rocha, G. B., Simas, A. M., Inorganic Chemistry, 44, 3299 (2005).
Rocha, G. B., Freire, R. O., Simas, A. M., and Stewart J. J. P., Journal of Computational Chemistry, 27, 1101 (2006).Leach, Andrew R. (2001). Molecular Modelling. Pearson Education Limited. 0582382106.