Effect of Ligand-Field Terms in Approximate Molecular-Orbital Calculations on Metal Complexes

An approximate molecular-orbital scheme is developed and used to assess the contribution of ligand-field terms in calculations of the electronic structure of inorganic complexes. Comparative calculations on the MnO4− ion by this and other methods are presented, and it is shown that the self-consistent charge distribution, and hence the interpretation of the nature of the bonding, is critically dependent on the formalism of the off-diagonal elements.