ON THE STRUCTURE, REACTIVITY AND RELATIVE STABILITY OF THE LARGE CARBON CLUSTER IONS C-62+, C-60+ AND C-58+

The exclusive metastable loss of C2 from C+62, C+60 and C+58 generated by laser ablation from graphite is studied using a high resolution reverse geometry mass spectrometer. Kinetic energy release distributions are peaked at low energies (≈0.2 eV) and fall off quasi-exponentially at higher energies. Successful modeling by statistical phase space theory indicates no reverse activation energy for C2-loss. A molten droplet of spheroidal geometry for the structure of these ions best fits the data. The modeling also indicates C2 is bound to C+62 by 3.0 eV and to C+60 and C+58 by ≈4.6 eV. Electronic rather than structural effects are suggested as the cause of the instability of C+62 relative to C+60 and C+58. Kinetic effects that reflect the instability of C+62 and to a lesser extent the stability of C+60 are suggested as the principal reasons why C+60 can be a dominant feature in the mass spectrum under favorable experimental conditions. © 1990.