Sequential ionization of C60 with femtosecond laser pulses

Multiply charged C-60(q+), q<6, is observed in the multiphoton ionization of C-60 With 790 nm, 25 fs pulses. Determination of the laser intensity dependence of the ion intensities indicates that the multiple ionization occurs predominantly sequentially. Coupling of the electronic excitation energy to vibrational degrees of freedom occurs in competition with further ionization. (C) 2001 American Institute of Physics.