-The radiation-induced fragmentation of the C 60 fullerene was investigated by the tight-binding electron-ion dynamics simulations. In intense laser field, the breathing vibrational mode is much more strongly excited than the pentagonal-pinch mode. The fragmentation effect was found more remarkable at long wavelength λ≥800 nm rather than the resonant wavelengths due to the internal laser-induced dipole force, and the production ratio of C and C 2 rapidly grows with increasing wavelength. By such fragmentation law, C atoms, C 2 dimers or large C n fragments could be selectively obtained by changing the laser wavelength. And the fragmentation of C 60 by two laser pulses like the multi-step atomic photoionization was investigated.

The time delays in photoionization of asymmetric diatomic molecules are numerically investigated using the technique of reconstruction of attosecond beating by interference of two-photon transitions (RABBITT). Our results show that two different oscillatory structures appear in the molecular photoionization time delays as the photoelectron energy changes, and the contribution of these two oscillations to the time delays varies with the nuclear distance. By using an analytical interference model, we demonstrate that one oscillation is traced back to the two-center interference and the other originates from the photoelectrons backward scattering. With the increases of internuclear distance, the backward scattering impact on the time delays is gradually distinct in a particular direction of the photoionization. The amplitude of the backward scattering induced oscillation decreases when the photoelectron energy increases. Furthermore, the stereo RABBITT time delays display a distinct downshift as the increases of asymmetry degree of molecules, which is attributed to the increasing depth of the additional Coulomb potential experienced by the ionized electrons.

Charge migration during light-matter interaction is one of the most fundamental processes which plays a key role in chemical and biological processes of molecule. The measurement of this process requires the extreme temporal and subatomic spatial resolutions. Here, we show that a scheme based on infrared pump and short extreme ultraviolet probe technique enables us to trace the laser-controlled electron motion with high spatiotemporal resolution. By numerically solving the time-dependent Schrödinger equation for H + 2 combined with a simple double-slit model, we demonstrate that the laser-controlled charge migration can be directly reconstructed from the interference patterns of the photoelectron spectrum.