Abstract
We investigated the direct ionization and desorption of solid C60 by the irradiation of femtosecond nonresonant (neutral and cationic states) pulses at 1.4 µm. We concluded that ion desorption is induced by Coulomb explosion. Initially formed highly charged molecular ions were annihilated with neighboring neutral or lower-charged ions, which finally resulted in singly charged C60. The electronically and vibrationally excited hot ions were formed by the release of excess energy after the charge redistribution, electron-hole recombination, and electron impact processes leading to delayed (thermal) ionization. Singly charged ions were finally emitted due to the high density of the surface charge.
