C61 CLUSTERS - AM1 COMPUTATIONS

The C61 clusters were studied using the AM1 quantum-chemical method. A full geometry optimization of the I(h), C2v and C(s) structures was p erformed, together with a vibrational harmonic analysis. The I(h) and C2v structures are located about 550 and 50 kJ mol-1, respectively, ab ove the C(s) species. The related structures with a triplet electronic state exhibit still lower energy (by about 150 kJ mol-1), compared wi th the singlet of the same point-group symmetry. No vibrational analys is of the triplet species could be performed because of SCF convergenc y difficulties.