Electronic and geometric structures of Co₂C_n^- and V₂C_n^-: Initial growth mechanisms of late and early 3d transition-metal carbide clusters

A study was conducted on the dicobalt carbide anions, Co₂C_n^- (n=2 and 3), as a representative of dimetallic carbides of the late 3d transition metals. As such, the electronic and geometric structures were obtained by the method and the calculation similar to those employed in the study of V₂C₂^-. Moreover, the different formation mechanisms of the carbide clusters were indicated between the early and late 3d transition metals.