Photoionization and fragmentation dynamics of C60

Photoionization of C60 by 15 ns laser pulses at 193 and 308 nm and by ca. 100 fs pulses at 310 and 620 nm has been studied with reflectron time-of-flight mass spectrometry. The initial fragmentation process is seen to be the ejection of Cn, n>2, as opposed to successive C2 evaporation. The fragment ions produced in this initial fragmentation step have sufficient internal energy to cool, by the emission of a C2 molecule in the field-free region of the mass spectrometer. Pump-probe experiments with 90 fs laser pulses at 620 nm give additional insights into the ionization mechanism.