THE LOCATION AND PARENTAGE OF ELECTRONIC TRANSITIONS OF HETERONUCLEAR DIATOMIC MOLECULES CONTAINING TRANSITION METALS, USING EMPIRICAL METHODS

Author Institution: Department of Chemistry, University of California, and Materials and Molecular Research Division; Department of Chemistry, University of MichiganThere are now many detailed analyses of electronic systems of heteronuclear diatomic molecules containing transition metals but, as yet, there has been no general theoretical treatment of the number, location and nature of the systems to be expected. While there are obvious theoretical difficulties in calculating the energy levels of homonuclear diatomic molecules, this is not always true for heteronuclear, particularly when the constituent atoms have widely disparate energy levels. It is possible to treat these molecules by a variant of Crystal Field Theory and to obtain parameters which are transferable, thereby enabling the location and identification of many electronic states to be `predicted' with useful precision. The `field' parameters, obtained from fitting the `one-electron' species, range from $10 cm^{-1}$, for I bound to metals of the first transition series, to $575 cm^{-1}$ for N bound to metals of the second transition series and there are regular and predictable variations for the other halogens and non-metal `ligands'. The magnitudes of the `one-electron' spin-orbit coupling constants also vary in a regular manner and, in many cases, serve as useful indicators to the atomic parentage of the molecular states. The extension to two- and three-electron systems will also be discussed