Behavior of silicon and germanium clusters on a C₆₀ fullerene

Behavior of silicon (Si) and germanium (Ge) atoms (or clusters) on the surface of a C₆₀ fullerene has been revealed by using time-of-flight mass spectroscopy and photoelectron spectroscopy. The mixed clusters of C₆₀Si_n and C₆₀Ge_m were generated by two-lasers vaporization of a molded C₆₀ rod and a Si (or a Ge) rod in He carrier gas. The size distributions of anionic and cationic C₆₀Si_n/C₆₀Ge_m clusters monotonically decreased with the number of Si/Ge atoms, and were limited only up to n = 4 and m = 3. The photoelectron spectra of C₆₀Si_n^- and C₆₀Ge_m^- are similar to that of pure C₆₀^- at m = 3, 4, whereas the spectra at n, m = 1, 2 are different from that of C₆₀^-. These results show that Si/Ge atoms assemble together into Si/Ge clusters on the C₆₀ cage with an increase in the number of Si/Ge atoms.