Atomic, Molecular, and Optical Physics Seminar/Attosecond
Quantum Dynamics Seminar
uFDr. Cheng Huang, UEC
^CgFMolecular dynamics in intense laser field
This talk will introduce three works during my PHD study, including above threshold ionization and nonsequential double ionization of molecules.
1. We investigate electron emissions from H2+ by circularly polarized laser pulses. The result indicates that most of electrons are emitted not at the instant when the electric field is parallel to the molecular axis, but hundreds of attoseconds later. The time delay results in the shift of electron emission direction with respective to the prediction of the tunneling theory. Furthermore, we find that the angular shift decreases with increasing the laser wavelength.
2. We investigate electron emissions in strong field enhanced ionization of asymmetric diatomic molecules by quantum calculations. Besides electron wave packet direct ionization from the up-field site (DIU), we find another two ionization channels, the field-induced excitation with subsequent ionization from the down-field site (ESID), and the up-field site (ESIU). The contributions from these channels depend on the molecular asymmetry and internuclear distance. This provides a more comprehensive physical picture for the enhanced ionization of diatomic molecules.
3. The effect of molecular alignment on the electron correlation in nonsequential double ionization is investigated. Compared with parallel molecules, the suppressed potential barrier for perpendicular molecules is higher, and the second electron is more difficult to ionize. Thus for perpendicular molecules the second ionization has longer time delay and has a larger probability to occur before the second field maximum, which results in more anticorrelated emissions.
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