A complete Intermediate Neglect of Differential Overlap model suitable for the examination of transition metal complexes is described. The model is characterized by the inclusion of all the one-center exchange terms necessary for rotational invariance and accurate spectroscopic predictions, as well as an accurate description of integrals involving 3d atomic orbitals. The model is within the unrestricted Hartree-Fock formalism, and a method for spin purification is described. Problems with convergence of the self-consistent field are discussed, and a method that has been found successful in aiding the convergence is outlined. The model has been applied to many transition metal systems. In this article the results of calculations on the chlorides of Fe, Co and Cu are described. The results of these calculations are compared with experiment, and with the results of calculations by other methods.

An intermediate neglect of differential overlap theory for transition metal complexes: Fe, Co and Cu chlorides

Electron transfer by copper centers.

Electronic properties of transition-metal oxides-II: Cation distribution amongst octahedral and tetrahedral sites

Electronic properties of transition-metal oxides—I: Distortions from cubic symmetry

Publisher Summary This chapter describes the electronic spectra in ionic crystals. The lowest energy spectra that occur both in the transition and post-transition ions in solids arise from electron jumps occurring principally within the metal ion. The analogy between the two groups has been illustrated for the low oxidation levels of the metal where s or d electrons are available to make a transition. An analogy may also exist for the higher oxidation levels in which no electron shells of the metal ion are available to make low-energy transitions. These ions exist in the form of molecules rather than as discrete ions. The same is true in the higher oxidation levels of the post transition metal ions. The problem of finding a zeroth-order approximation in terms of which the spectra maybe understood qualitatively is presented, and that may serve as a starting point for calculation. This was a straightforward problem for molecular crystals, and for the f- and d-electron states of rare earth and transition metal ions.

L. Helmholz

Papers

The Crystal Structure of Cesium Chlorocuprate, Cs2CuCl4, and the Spectrum of the Chlorocuprate Ion