里德堡H原子在非均匀场及金属面附近的光电离

发布时间：2018-01-04 22:11

本文关键词：里德堡H原子在非均匀场及金属面附近的光电离　出处：《鲁东大学》2017年硕士论文　论文类型：学位论文

【摘要】：激光技术的发展使激光与原子分子之间的相互作用的研究受到人们的广泛关注。光电离显微成像技术的出现,使得用原子的光电离来研究电子的显微成像成为了原子与分子物理领域研究的前沿课题。将原子置于不同的外场条件或表面附近,原子外层的电子在吸收足够的光子能量后发生电离,以电子波的形式从原子核向四周传播,离开原子实区域后,在外场和表面的作用下运动,最终沿着不同的轨道运动到探测器平面上的一点,由于不同电子波之间存在干涉作用,会在探测器上形成具有一系列振荡结构的电子干涉图像。近年来,里德堡氢原子在静电场、磁场、金属面附近、弹性表面附近等单一场或表面附近的光电离显微研究已经近于完备。这些研究为光电离显微实验中对电离电子动力学的宏观调控提供了丰富的理论依据。但是对于里德堡原子在非均匀场以及表面附近光电离显微成像的研究至今未见报道。本文将运用半经典开轨道理论与镜像电荷理论研究里德堡氢原子在非均匀电场及金属面附近光电离的动力学。该研究对丰富里德堡氢原子光电离体系,更好的理解外场对原子光电离过程的调控作用有重要意义。本文的研究主要包含四个部分:1.运用半经典开轨道理论研究了里德堡氢原子在梯度电场中的光电离。构建了里德堡氢原子在梯度电场中光电离的物理模型。通过标度变换给出了梯度电场中高激发态氢原子的哈密顿量。再通过数值计算来模拟电子电离的运动轨道,并计算和分析了探测器平面上电子的几率密度分布。研究表明:相对于里德堡氢原子在匀强电场中的光电离来说,在梯度电场中,能够到达探测平面的电离电子的轨道数目增多,其相应的电子几率密度图像上的振荡结构变得复杂。随着电场梯度的增加,其对电子运动的影响开始显现,电子能够到达的最大半径逐渐变小,振荡结构的范围也随之变窄。2.运用半经典近似理论结合镜像电荷理论,研究了里德堡氢原子在金属面附近静电场中的光电离。研究发现电子几率密度受到标度电场强度和标度能的影响非常明显。随着标度电场强度增加,能够到达探测平面的电子轨道数目减小,使得电子几率密度图像的振荡结构变得简单。当标度电场强度非常大时,金属面的作用几乎可以忽略,该体系近似接近于里德堡氢原子在静电场中的光电离。另外,标度能对该体系的电子几率密度也有显著的影响。因此,我们可以通过改变标度电场强度和标度能来实现对里德堡氢原子在金属面附近光电离的调控。3.运用半经典的开轨道理论,第一次研究了里德堡氢原子在梯度电场及金属面附近的光电离。计算了不同标度电场梯度和不同标度能下探测平面上的电子通量密度分布。由于不同经典电子轨道之间的相互干涉作用,在电子通量密度图像上出现了一系列复杂的振荡结构。研究表明,这些振荡结构与标度电场梯度、标度能量和金属面放置的位置有关。另外,详细讨论了电子通量密度与不同类型轨道之间的关系。如果外场和金属表面满足一定的条件,电子通量密度的干涉图样能够在里德堡氢原子的光电离实验中观测到。4.研究了里德堡氢原子在梯度电场和磁场中自电离随时间的演化,着重讨论了梯度电场和磁场对电子运动的影响。在光电离的过程中出现了一系列的电子脉冲。当标度电场梯度很小时,氢原子在梯度电场和磁场的光电离过程类似于氢原子在静电场和磁场中的光电离。随着标度电场梯度的增加,能够在给定时间内到达探测器平面的电子轨道数目减小,使其θ-t曲线和电离率曲线变得简单。随着标度磁场强度的增加,电离电子的动力学行为开始变得混沌,θ-t曲线出现一种“韵律结构的自相似性”的分形结构。另外,氢原子光电离的动力学行为还受标度能的影响。本文共分为六章:第一章为引言,主要介绍了选题意义、里德堡原子和非均匀电场、半经典开轨道理论、相关领域的研究现状以及创新点。第二章研究了梯度电场对里德堡氢原子光电离的影响。第三章运用半经典的开轨道理论结合镜像电荷理论研究了里德堡氢原子在金属面附近静电场中的光电离。第四章为第三章的深化,将静电场改为梯度电场,研究了梯度电场和金属面对里德堡氢原子光电离的影响。第五章研究计算了里德堡氢原子在非均匀电磁场中的光电离随着时间的演化关系。第六章为文章的总结以及对未来工作的期望。
[Abstract]:The development of laser technology to study the interaction between laser and atom molecules have attracted extensive attention. The photoionization appearance of micro imaging technology, making use of the photoionization of electron microscopic imaging has become a research field of atomic and molecular physics subject. The atoms under different field conditions or near the surface the outer electron atom, ionization occurs in the absorption of photon energy enough, to the electronic wave form from the nucleus to spread around, leaving the atom movement in the field area, and surface under the action of the final orbital motion along different detector plane point, due to the existence of interference between different electronic wave form of electronic interference image has a series of oscillation structure in the detector. In recent years, the field of Rydberg hydrogen atom in the electrostatic field near the metal surface, and the surface of the elastic A single field or near surface from the microscopic study was almost complete. These studies provide abundant theoretical basis for macro-control of photoionization dynamics in electron microscope experiment. But for the Rydberg atoms in the study of non uniform field and near the surface of photoionization microscopy has not been reported. This paper will use the half the classical open orbits theory and image charge theory research of Rydberg hydrogen atom in inhomogeneous electric field near the metal surface and the photoionization dynamics. The research is to enrich the system of Rydberg hydrogen atom photoelectric, a better understanding of the atomic field has important significance from the regulation of the photoelectric process. This research mainly includes four parts: 1. the use of photoelectric the semi classical open orbits theory of Rydberg hydrogen atom in the gradient in the field. From the construction of Rydberg hydrogen atom in the gradient electric field photoionization Physical model. By scaling transformation gives the Hamiltonian of highly excited hydrogen atom gradient electric field. The motion track of numerical simulation of electron ionization, analyzes the probability density distribution of electron detector plane is calculated and. Research shows that compared with the photoelectric Rydberg hydrogen atom in a uniform electric field in the. In the gradient field, can reach the detection number of ionization electron orbit plane increases, the electron probability density image on the corresponding oscillation structure is complicated. With the increase of the electric field gradient and its influence on the movement of electrons began to appear, to reach the maximum radius of electron becomes small and the range of oscillation structure also narrowed.2. by using the semi classical approximation theory combined with image charge theory, the study of the optical Rydberg hydrogen atom near a metal surface in electrostatic field. From the study found that the electronic probability density by To influence the scale of electric field intensity and scale can be very obvious. With the scale of electric field strength increases, can reach the detection of electronic orbital plane number decreases, the oscillation probability density structure of electronic image becomes simple. When the scale of electric field intensity is very large, the metal surface is almost negligible, the approximation is close to the Rydberg system the hydrogen atoms in the electrostatic field from the photo. In addition, scaling to the electronic probability density of the system have a significant impact. Therefore, we can change the scale of electric field intensity and scale can be achieved on Rydberg hydrogen atom near a metal surface photoionization control of the.3. using the semi classical open orbits the theory, first studied the photoelectric Rydberg hydrogen atom near a metal surface and electric field gradient. From different scale and different electric field gradient scale electron flux density detection plane points calculation Cloth. Due to differences between classical electron orbit interaction, a series of complex oscillation structure in the electron flux density images. The results show that these oscillations and the scale structure of the electric field gradient scale, energy and metal surface placement. In addition, discusses the relationship between the electron flux density and the different the type of track. If the field and metal surfaces meet certain conditions, the interference pattern of electron flux density in photoelectric Rydberg hydrogen atom from the observed.4. of Rydberg hydrogen atom in electric and magnetic field gradient in self ionization time evolution, discusses the influence of gradient electric field and magnetic field on electron motion in the process of photoionization. Appeared in a series of electronic pulse. When the scale of electric field gradient is very small, the hydrogen atoms in the photoelectric gradient electric field and magnetic field is similar to the process of hydrogen Optoelectronics in electrostatic field and magnetic field. With the increase of the scale from the electric field gradient, can reach the number of electronic track detector plane decreases in a given period of time, the theta -t curve and the ionization rate curve becomes simple. With the increase of the scale of the magnetic field strength, the dynamic behavior of ionization electrons became chaotic, theta the -t curve shows a "self similarity" prosodic structure fractal structure. In addition, dynamic behavior of photoionization of hydrogen atom is also affected by the scale of energy. This paper is divided into six chapters: the first chapter is the introduction, mainly introduces the significance of the topic, Rydberg atoms and non-uniform electric field, the semi classical open orbits theory the research status of related fields, as well as innovation. The second chapter studies the influence of gradient electric field on Rydberg photoionization of hydrogen atom. The third chapter uses the semi classical open orbits theory combined with the theory of the image charge Rydberg hydrogen Optoelectronic near a metal surface in electrostatic field. From the fourth chapter to the third chapter of the deepening of the electrostatic field to study the electric field gradient, gradient field and metal effect on photoionization of Rydberg hydrogen atom. The fifth chapter studies the calculation of the photoelectric Rydberg hydrogen atom in non-uniform electromagnetic field with time evolution from. The sixth chapter is the summary and expectation for the future work.

【学位授予单位】：鲁东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O562

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