A group theoretical paradigm for describing the skeletal molecular orbitals of cluster compounds. Part 2. Bispherical clusters

Abstract

Stone's Tensor Surface Harmonic Theory has been extended to capped and raft clusters where the cluster atoms lie on the surface of two concentric spheres. The skeletal molecular orbitals of these bispherical clusters possess radial as well as tangential nodes. Group theoretical techniques enable the symmetries and quantum numbers L of the skeletal molecular orbitals to be evaluated. The bonding characteristics of bispherical clusters are dominated by the bonding molecular orbitals of the inner polyhedron, but some additional skeletal bonding molecular orbitals may be generated from the ^π orbitals of the outer polyhedron. Spherical (or pseudo-spherical) clusters are created by distorting the bispherical clusters until all the atoms lie approximately on the surface of one sphere. These clusters are characterised by (N+ 1) skeletal electron pairs.