Kinetic energies of (n ⩽ 58) fragment ions produced by nanosecond laser impact on C60

Laser-induced fragmentation of C60 has been studied using a time-of-flight mass spectrometric technique. The average kinetic energies of fragment ions C n + (n ⩽ 58) have been extracted from the measured full width at half maximum (FWHM) of ion beam profiles. The primary formation mechanism of small fragment ion C n + (n < 30) is assumed to be a two-step fragmentation process: C60 sequential decay to unstable C 30 + ion and the binary fission of C 30 + . Considering a second photo absorption process in the later part of laser pulse duration, good agreement is achieved between experiment and theoretical description of photoion formation.