Theoretical Study Of The Time-dependent-wave-packet Dynamics From Femtosecond To Attosecond

In this thesis, the photoelectron spectra of molecules have been calculated by the time-dependent-wave-packet method, and its extension is applied to study the dynamics of an electron in an intense field. All these conclusions are very important for understanding the dynamical behaviors of molecules. The main results are summarized as follows:1. Firstly,"what is intense laser field"is introduced, then the phenomena of above-threshold ionization and high-order harmonic generation et al. have been explained. Finally, we emphasize the importance of the returning electron dynamics.2. The fundamental theory of the wave-packet dynamics associated with our work is introduced. The basic theories of coupled energy levels, field-matter interaction, and multi-photon ionization in the intense field et al. have been explained.3. The photoelectron spectra of N₂ have been calculated by the time-dependent-wave-packet method, and our results accord well with the experiment obtained. After explaining the reasons that most ionizations occurring from B²Î£_u⁺ state, we emphasize that longer wavelengths are easier to induce resonance.