H. Zetergren, G. Sánchez, S. Díaz-Tendero, M. Alcamí, and F. Martín
Theoretical study of the stability of multiply charged C70 fullerenes.
We have calculated the electronic energies and optimum geometries of C70q+ and C68q+fullerenes (q=0–14) by means of density functional theory. The ionization energies for C70 and C68 fullerenes increase more or less linearly as functions of charge, consistent with the previously reported behavior for C60 and C58 [S. Díaz-Tendero et al., J. Chem. Phys.123, 184306 (2005)]. The dissociation energies corresponding to the C70q+ → C68q++ C2, C70q+→C68(q−1)++C2+, C70q+→ C68(q−2)++ C++C+, C70q+→C68(q−3)++C2++C+, and C70q+→C68(q−4)++C2++C2+ decay channels show that C70q+ (like C60q+) is thermodynamically unstable for q⩾6. However, the slope of the dissociation energy as a function of charge for a given decay channel is different from that of C60q+fullerenes. On the basis of these results, we predict q=17 to be the highest charge state for which a fission barrier exists for C70q+.