THE ABDUS SALAM INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS OPTIMIZATION OF C20 ISOMERS STRUCTURE

We have performed geometry optimization of various possible planar and threedimensional C20 geometries. The planar structures considered include a linear chain, a monoclinic ring, and a bicyclic bow tie; while the three-dimensional geometries consisted of a bowl or corranulene structure and a fullerene cage. In agreement with Wang et al MP2's calculations, our results predict the corranulene bowl to be the lowest energy structure. From the ground state geometry to the highest energy, considered C20 structures, listed in increasing energy, are bowl, cage, bow tie, ring and chain. For the ring and bow tie isomers, the shape of the optimized structure deviates from that of the initial configuration; while the shape of the optimised bowl, cage and chain remains unchanged.