Recurrence Spectra Of Rydberg Multielectron Atoms In The Parallel Electric And Magnetic Fields

The photo-absorption phenomenon of highly excited Rydberg atoms in strong external fields has attracted much attention in recent years, which is a typical example for understanding the conception of quantum chaos. The semiclassical closed-orbit theory has been extensively used to explain this phenomenon due to its enlightened physical picture and wide availability such that has become a bridge between quantum and classical theory. This theory has successfully calculated and interpreted the photo-absorption spectra of H ? and has been applied to describe the recurrence spectra of photo-excitation, wave packet dynamics of some atoms and molecules such as H , Li atoms, H 2, NO molecules and so on. Corresponding extended methods have applied to study the transport properties of micro-cavity and the investigation on the atoms life in environment.Other than the hydrogen atom, a theoretically studying of the multielectron atom is more difficult. The multielectron atoms are quantum atomic systems whose underlying classical dynamics is chaotic induced by ionic core scattering. Previously theoretical and experimental studies have found that the effects of the non-hydrogenic ionic core should be considered. It is core scattering that leads to new recurrence peaks called combination recurrence. Therefore, it is necessary to correct and extend the primitive standard closed-orbit theory to include this affect.In this paper, by using special regions-splitting consistent and iterative method combined together with the quantum defect theory and model potential approach, we calculate the closed orbits and the recurrence spectra in frame of extended closed-orbit theory with finite resolution. The spectral structure is measured in larger energy scale (or equivalent to a shorter time scale). That is to say, we only consider the contributions of closed orbits with smaller actions that are the most decisive for the spectral structure. We obtained the recurrence spectra of triplet helium and lithium atoms with n≈40 and M =1 in parallel electric and magnetic fields at scaled energyε= ?0 .03. The results reveal that the core-scattering effects are important, particularly, the short-range model combining with the repulsive potential have remarkably changed both the closed orbits and wave function of the electrons, thus altered obviously the yielded recurrence spectra, which can be readily conformed by comparison with the recurrence spectra of H atoms at the same condition.In order to discuss the effects of magnetic quantum number on the recurrence spectra, we calculate the recurrence spectra of M =0 He and Li atoms in the parallel electric and magnetic fields at scaled energyε= ?0 .03 and scaled electric field f = 0.01. Comparing the two cases, we find that the dynamical feature of M =1 is different from M =0. The centrifugal barrier make the diffraction arising from ionic core and the correlation of electrons weaken, which plays a great role in the recurrence spectra.For the studies of multielectron Rydberg atoms, our works are not only the extension but also the validation and supplement for the closed-orbit theory. So far, there has been no experiments of M =1 He and Li atoms in the parallel electric and magnetic fields that compared to the recurrence spectra in theory, we expect that our calculations may help to design new experiment in future.This thesis consists of six chapters. The first chapter is summarization, which briefly introduces the development history of semiclassical closed-orbit theory. The second chapter is devoted to the model potential and the scaled variable recurrence spectroscopy. We give the proper model potential of multielectron atoms and the scaled variable in parallel external electric and magnetic fields. The third chapter describes the closed orbit theory for multielectron Rydberg atoms. The fourth chapter presents the calculating results of the recurrence spectra of Li ( M =0, M =1) Rydberg atoms in parallel electric and magnetic fields and compares our results to the hydrogen situation. Our emphasis is to analyze the effects of the model and short-range repulsive potentials. The fifth chapter presents the calculating results of the recurrence spectra of He ( M =0, M =1) Rydberg atoms in parallel electric and magnetic fields. By comparison between two different magnetic quantum numbers, the effects of the short-range repulsive potential with cylindrical symmetry have been analyzed in detail. The sixth chapter is the conclusion of this work and expectation.