PHOTOIONIZATION AND FRAGMENTATION DYNAMICS OF C-60

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 t ime-of-flight mass spectrometry. The initial fragmentation process is seen to be the ejection of C(n), n > 2, as opposed to successive C2 ev aporation. The fragment ions produced in this initial fragmentation st ep have sufficient internal energy to cool, by the emission of a C2 mo lecule in the field-free region of the mass spectrometer. Pump-probe e xperiments with 90 fs laser pulses at 620 nm give additional insights into the ionization mechanism.