Size dependence of ionization potentials and dissociation energies for neutral and singly-charged Cn fullerenes (n = 40-70)

Dissociation energies and ionization potentials of neutral and singly-charged fullerenes have been obtained from density functional theory calculations for sizes ranging from 40 to 70 atoms. Good agreement with available experimental data has been obtained. Our results confirm that magic number fullerenes with n = 50, 60 and 70 present the largest ionization potentials and dissociation energies. We have found that the most stable isomer for n = 62 is a non-classical structure with a chain of four adjacent pentagons surrounding a heptagon, and for n = 50 is a structure of D3 symmetry that violates the pentagon adjacency penalty rule. Both unusual structures lead to the best agreement with experiment.