PHOTOFRAGMENTATION OF C-60

Photo-ionisation and -fragmentation of C60 by 15 ns excimer laser puls es at 308 nm and 193 nm as well as 0.8 ps laser pulses at 193 nm has b een studied with reflectron time-of-flight mass spectrometry. The init ial fragmentation process is ejection of C-n, n > 2, as opposed to suc cessive C-2 evaporation. Studies of the relative intensities of metast able fragmentation processes compared with direct fragmentation provid e new insight into the fragmentation mechanism and provide a thermomet er for the internal energy of C-60(+) prior to fragmentation. The prop osed mechanism is in agreement with measurements of the fragment ion k inetic energies. The results are compared with molecular dynamics simu lations.