Sequential ionization of C-60 with femtosecond laser pulses

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