An ab initio study of the equilibrium structure and bonding of FeC2 and FeC3 clusters and their anions

An ab initio multiconfigurational CASSCF/CASPT2 approach has been used to calculate the electronic structure of the equilibrium conformations of the FeC2, FeC3 complexes and their anions. We have found cyclic C2v structures as the ground states for these clusters, except for the FeC3− cluster for which a C∞v linear structure is predicted. Formally the electronic structure of the FeCn (n=2,3) clusters can be considered as Fe2+Cn2−. The computed adiabatic electron affinities correspond well with the photoelectron spectroscopic data.