ENERGETIC ANALYSIS OF PENTAGON ROAD INTERMEDIATES OF C-60-BUCKMINSTERFULLERENE FORMATION

We report an energetic analysis of the principal intermediates of the pentagon road (PR) scheme for formation of C-60-buckminsterfullerene. All calculations were initially performed using the tight-binding semi empirical method. For selected cases, more rigorous 3-21G/HF and 3-21G /B3LYP calculations were carried out. The first part of this study inc ludes an energetic comparison between the 30-, 40-, and 50-atom PR int ermediates and a representative group of 30-, 40-, and 50-atom carbon clusters. While C-30 PR is higher in energy than a large variety of gr aphene sheets and fullerenes, C-40 PR and C-50 PR are considerably low er in energy than many other isomers; only fullerenes are more stable. Additionally, we examine a plausible mechanism by which C-50 PR rearr anges to form a C-50 cage with D-5h symmetry. Because of its large ene rgy barrier, this process is unlikely to affect the C-60 growth mechan ism.