Structure of small carbon clusters: Cyclic ground state of C(6).

The study of small clusters of carbon atoms has been an area of intense interest recently. Though clusters as large as 200 atoms have been seen experimentally, very little structural information is known for clusters containing more than 4 atoms. There have been a few previous semi-empirical calculations on the six-atom cluster C(6) which were mainly based on a linear geometrical arrangement, though a compact octahedral structure has also been proposed in one of the studies. In this work, accurate ab initio calculations with the inclusion of electron correlation corrections have been performed to investigate the nature of the structures and energies of different C(6) isomers.