IR, NIR, and UV Absorption Spectroscopy of C602+ and C603+ in Neon Matrixes

C-60(2+) and C-60(3+) were produced by electron-impact ionization of sublimed C-60 and charge-state-selectively codeposited onto a gold mirror substrate held at 5 K together with neon matrix gas containing a few percent of the electron scavengers CO2 or CCl4. This procedure limits charge-changing of the incident fullerene projectiles during matrix isolation. IR, NIR, and UV-vis spectra were then measured. Ten IR absorptions of C-60(2+) were identified. C-60(3+) was observed to absorb in the NIR region close to the known vibronic bands of C-60(+). UV spectra of C-60, C-60(+), and C-60(2+) were almost indistinguishable, consistent with a plasmon-like nature of their UV absorptions. The measurements were supported by DFT and TDDFT calculations, revealing that C-60(2+) has a singlet D-5d ground state whereas C-60(3+) forms a doublet of C-i symmetry. The new results may be of interest regarding the presence of C-60(2+) and C-60(3+) in space.