Structure and stability of molybdenum carbide clusters (MoC₄)_n (n=1 to 4) and their anions

We study the structure and stability of recently discovered molybdenum carbide clusters (MoC₄)_n and (MoC₄)_n^- (n=1 to 4) using local-density-functional calculations. Our results suggest that small clusters are planar and larger ones have three-dimensional structures. The carbon atoms in the clusters have the tendency to form a chain or ring structure similar to that in small all-carbon clusters. The molybdenum carbide clusters are stable with binding energies per atom comparable to those of the metallo-carbohedrene and fullerene clusters. The electron affinities and fragmentation pathways of these clusters have also been determined and compared with available experimental data.