MNDO, or Modified Neglect of Diatomic Overlap is a semi-empirical method for the quantum calculation of molecular electronic structure in computational chemistry.
It is based on the Neglect of Diatomic Differential Overlap integral approximation.
It is part of the MOPAC program and was developed in the group of Michael Dewar.
The extension by W. Thiel's group, called MNDO/d, which adds d functions, is widely used for organometallic compounds.
In this way, the method should give better results for systems where correlation is particularly important and different from that in the ground state molecules from the MNDO training set.