Aspects of the MNDO semiempirical method

After an examination of the MNDO method and the approximations used therein, the parameters needed for the construction of the Hamiltonian and the parametric method used to derive them are introduced. The results of the successful parametrization of two elements, bromine and iodine, follow together with analysis and discussion. The MNDO method is then applied to three problems of chemical and theoretical interest, namely the bonding in borane clusters, the mechanism of the Claisen rearrangement, and a comparison of nucleophilic displacement reactions at carbon and silicon centers. In all cases the results necessitated a re-examination of the current prevailing views in these fields.