The project proposed for funding here deals with the expansion of a next generation model in semi-empirical molecular orbital treatments. The new approach is called SAM1 (for Semi-empirical AB Initial Method Version 1). SAM1 is different from present methods in that it explicitly computes two-electron repulsion integrals via a minimum Gaussian basis set, bringing new theoretical rigor to the NDDO model on which such successful techniques as AM1 and MNDO are based. Many of the aspects that make semi-empirical methods so attractive and useful to such a wide audience (i.e. speed and implicit accounting for electron correlation) are retained in SAM1. We propose here to expand and apply the SAM1 method to a variety of new elements and to test its performance on the prediction of chemical phenomena. Parameter sets for carbon (C), hydrogen (H), oxygen (O), nitrogen (N), fluorine (F), chlorine (Cl), bromine (Br), and iodine (I) have already been derived. We will expand this set of elements to sulfur (S), phosphorous (P), silicon (Si), arsenic (As), and copper (Cu), allowing SAM1 to be applied to a wide range of chemistry including the processes of life, materials science, and many reactions of industrial importance. SAM1 represents the first practical and accurate computational treatment of systems involving transition metals.
