Photoionization Microscopy Of The Rydberg Hydrogen Atom In A Non-uniform Field Near A Metal Surface

With the development of laser technology,the research of the interaction between the laser and the atom and molecules is attracting widespread attention.The emergence of the photoionization microscopic imaging technology makes the study of the photoionization of highly excited atoms become the front research area in atomic and molecular physics.Put the atoms in different strong fields or near surfaces,after the electron in the atom absorbs enough photon energy,it will be photoionized and propagates outward in the form of electronic wave.As it is far away from the atomic core,due to the influence of the external fields and the surfaces,the electron wave travels along different trajectories may arrive at a given point on the detector plane.The interference of these electron waves induces a series of oscillatory structure in the interference pattern on the detector plane.In recent years,the study of the photoionization microscopy of the Rydberg hydrogen atom in the static electric field,magnetic field,near the metal surface or the elastic surface has been researched completely.These studies provide abundent theoretical foundations for the experiment research on the macro-control of the ionized electron dynamics in the photoionization microscopy.However,for the photoionization of Rydberg hydrogen atom in the non-uniform external fields and near the surfaces,no reports have been given up till now.In this paper,we study the photoionization microscopy of the Rydberg hydrogen atom in the non-uniform electric field and near a metal surface based on the semi-classical open theory combined with the electrical image method.This research has important significance to enrich the photoionization system of the Rydberg hydrogen atom and have a better understanding of the control effect of the external field on the photoionization process.The main research of this thesis includes four aspects:1.Based on the semi-classical open-orbit theory,we study the photoionization microscopy of the Rydberg hydrogen atom in the gradient electric field.We establish a schematic plot for the photoionization of the Rydberg hydrogen atom in the gradient electric filed.Through a scaled transformation,we obtain the Hamiltonian of the high excited hydrogen atom in the gradient electric filed.Then we simulate the electrontrajectory with the help of the numerical calculation,calculate and analyze the electron probability density distribution on the detector plane.The calculation results suggest:compared to the photoionization of Rydberg hydrogen atom in a uniform electric field,in the gradient electric field,the number of the electron trajectories arrived at the detector plane becomes increased,which makes the oscillatory patterns in the photoelectron probability density distribution become complicated.With the increase of the electric field gradient,its influence on the movement of the electron becomes apparent,the maximum impact radius that the electron can reach the detector plane becomes smaller and the oscillating region in the probability density distributions becomes narrower correspondingly.2.On the basis of the semi-classical theory combined with the electrical image method,we have studied the photoionization of the Rydberg hydrogen atom in the static electric field near a metal surface.Our research suggests that the electron probability density distributions depend sensitively on the scaled electric field strength and the scaled energy.With the increase of the scaled electric field,the number of the electron trajectories arrived at the detector plane becomes decreased,which makes the oscillatory structure in the electron probability density interference pattern get less complicated.When the scaled electric field is very large,the influence of the metal surface can be neglected and the system approaches to the photoionization of the Rydberg hydrogen atom in a static electric field.In addition,the scaled energy can also have influence on the electron probability density distributions.Therefore,we can control the photoionization of the Rydberg atom near a metal surface by changing the electric field strength and the scaled energy.3.Using a semi-classical open theory,we investigate the photoionization of the Rydberg hydrogen atom in a gradient electric field near a metal surface for the first time.The electron flux distributions on a given detector plane have been calculated for different gradient electric field and different scaled energy.It is shown that owing to the interference effects of the electron wave traveling along various classical orbits,a serier of oscillatory structures appear in the electron flux distribution.And the oscillatory structures depend on the electric field gradient,the scaled energy and the position of the metal surface sensitively.In addition,the relation between the electronflux distribution and the types of the electron trajectory is also discussed in great detail.Through our research,we predict that the interference patterns in the electron flux distributions could be observed in an actual photoionization microscopy experiment if the external electric field strength and the position of the detector plane are reasonable.4.The evolution of the autoionization of a hydrogen atom in a magnetic field plus a gradient electric field with the time have been investigated,with a particular emphasis on discussing the influence of the gradient electric field and the magnetic field on the movement of the electron.The results show that a train of electron pulses appear in the ionization process.As the scaled gradient electric field is very small,the ionization process of the hydrogen atom in the gradient electric field and magnetic field is nearly the same as the case of hydrogen atom in the uniform electric field and magnetic field.With the increase of the scaled electric field gradient,the number of the electron trajectories arrived at the detector becomes decreased,which makes the θ-t curve and the ionization rate curve become simple.With the increased of the scaled magnetic field,the dynamics of the ionized electron becomes chaotic.An“epistrophic self-similarity” fractal structure appears in the θ-t curve.In addition,the dynamics of the photoionized hydrogen atom can also be affected by the scaled energy.This paper is divided into six chapters.The first chapter is introduction,we mainly introduces the significance of this research,the Rydberg atom and non-uniform electric field,the semi-classical open theory,the domestic and foreign research status and the innovation of this paper.In the second chapter,we study the influence of the gradient electric field on the photoionization microscopy of Rydberg hydrogen atom.In the third chapter,we research the photoionization of the Rydeberg hydrogen atom in a static electric field near a metal surface.The fourth chapter is a further research of the third chapter,we change the static electric field into a gradient electric field,and study the influences of the gradient electric field and metal surface on the photoionization of the Rydberg hydrogen atom.In the fifth chapter,we investigate the evolution of the photoionization of the hydrogen atom in the non-uniform electric field plus a magnetic field with the time.The sixth chapter gives the conclusions of this paper and the prospects of the future research.