C 61 clusters: AM1 computations

Abstract

The C 16 clusters were studied using the AM1 quantum-chemical method. A full geometry optimization of the I h, C 2v and C s structures was performed, together with a vibrational harmonic analysis. The I h and C 2v structures are located about 550 and 50 kJ mol −1, respectively, above the C s, species. The related structures with a triplet electronic state exhibit still lower energy (by about 150 kJ mol −1), compared with the singlet of the same point-group symmetry. No vibrational analysis of the triplet species could be performed because of SCF convergency difficulties.