Excitation, Fragmentation and Control of Large Finite Systems: $\mathrm{C_{60}}$ in Moderately Strong Laser Fields

Recent progress in the understanding of the primary excitation mechanisms of the C$_{60}$ fullerene in intense laser pulses is reported. By analyzing mass spectra as a function of pulse duration, laser intensity and time delay between pump- and probe pulse insight into fundamental photoinduced processes such as ionization and fragmentation is obtained. Using ultrashort sub-10fs pulses excitation times are addressed which lie well below the characteristic time scales for electron–electron and electron–phonon coupling. The measured saturation intensities of multiply charged parent ions indicate that for higher charge states the well known C$_{60}$ giant plasmon resonance is involved in creating ions and a significant amount of large fragments through a non-adiabatic multi-electron dynamics. To enhance the formation of large fragments femtosecond laser pulses tailored with closed-loop, optimal control feedback were used. A characteristic pulse sequence excites oscillations in C$_{60}$ with large amplitude by coherent heating of nuclear motion. Again, the experimental findings can be understood by a laser-induced multi-electron excitation via the electronically excited resonance followed by efficient coupling to the radial symmetric breathing vibration of C$_{60}$