Complete bond force fields for trivalent and deltahedral cages: Group theory and applications to cubane, closo-dodecaborane, and buckminsterfullerene

Group theory is used to define complete force fields for deltahedral and tr ivalent molecular skeletons in terms of bond stretches, and bond stretches and slides, respectively. Analysis of ab initio Hessian matrices shows the delocalized nature of the force field in boranes and the relatively localiz ed force field in C-60, where only interactions of bonds in adjacent rings or separated by at most three edges of the truncated icosahedron show signi ficant interaction.