Ground states of molecules. 38. The MNDO method. Approximations and parameters

The basic approximations of the MNDO (modified neglect of diatomic overlap) method are described including a semiempirical model for the two-center repulsion integrals. Parametric functions for the various terms in the MNDO Fock matrix are then chosen which contain atomic parameters only (no bond parameters). Using a nonlinear least-squares iterative optimization technique, numerical values of the parameters are determined for the elements H, C, N, O. Finally, the main differences between the MNDO and MINDO methods are discussed.