Case studies of atomic processes in strong fields: New aspects of multiphoton and nonlinear dynamics
The dynamic processes in the strong interaction of atomic systems and strong laser fields and magnetic fields are studied in the thesis. The dissertation consists of five parts. (i) The effects of pulse shape of a strong laser field in multiphoton processes are studied analytically for the first time to explore more deeply the underlying dynamics. In terms of the many-mode Floquet theoretical approach, a generalized pulse area concept is developed and is proved to be useful in the analytic prediction of the multiphoton excitation probability. (ii) In the presence of super-strong (>10{sup 16}{omega}/cm{sup 2}), pulsed laser fields, the ionization dynamics of the relativistic hydrogenic electrons are studied in detail in terms of the Monte-Carlo classical trajectory method. The difference in the ionization between relativistic calculations and non-relativistic calculations is shown in both the angular distribution and the energy spectrum of the photoelectrons. The strong effect of the magnetic field, the Aharonov-Anandan phase (AA phase) in a cyclic quantum evolution of any spin j system is studied in terms of the method of generalized coherent-state technique based on the SU(2) group. An analytical formula for the AA phase is found in terms of external physical parameters. (iv) A model of a dissipative nonlinear quantum system is investigated in terms of one-mode Floquet approach. New features, namely quantum limit cycles and fractal patterns, are found in the presence of a monochromatic laser field. (v) Based on the development of a spectrum transformation Lanczos algorithm and a generalized RRGM method, the relation between the irregular motion and nonseparable diamagnetic hydrogen atom is studied and demonstrated in terms of nodal patterns of wavefunctions. The study is further extended to the positive region, where an explanation is made of the ordered Rydberg progression observed experimentally.
- Research Organization:
- Kansas Univ., Lawrence, KS (United States)
- OSTI ID:
- 121339
- Resource Relation:
- Other Information: TH: Thesis (Ph.D.); PBD: 1992
- Country of Publication:
- United States
- Language:
- English
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