氢负离子在磁场和金属面附近电子通量分布的研究

利用半经典开轨道理论, 研究了磁场和金属面附近氢负离子的剥离电子通量分布, 并揭示了电子通量分布中的振荡结构与经典轨道之间的关系.固定离子到金属面的距离, 研究了不同的磁场强度对电子通量分布的影响. 结果表明, 由于与电子通量分布相联系的剥离电子的经典轨迹增加, 随着磁场强度的增加, 通量分布变得复杂. 此外发现剥离电子的能量变化也会影响电子通量分布. 因此可以通过改变磁场强度大小和剥离电子的能量来调控剥离电子通量分布和干涉图样. 研究结果对于理解负离子在外场、表面附近的电子流通量和剥离电子干涉图样问题以及将来实验研究负离子的光剥离显微问题都可以提供一定的参考. 关键词： 开轨道理论 电子通量 金属面 磁场     

氢负离子剥离电子通量的数值研究

本论文利用杜,赵等人的半经典轨道理论,推导了电场和金属面同时存在时,氢负离子的剥离电子通量分布,并对干涉图样进行了数值模拟。结果发现剥离电子通量分布不仅与激光光子能量和外场有关,并且敏感地依赖于金属面与氢负离子之间的距离。这些结果可以应用于许多重要的研究领域,包括超快激光表面催化,更准确的测量电子亲和力和控制低能的光电子和表面的相互作用等。     

氢负离子剥离电子通量的数值研究

本论文利用杜,赵等人的半经典轨道理论,推导了电场和金属面同时存在时,氢负离子的剥离电子通量分布,并对干涉图样进行了数值模拟。结果发现剥离电子通量分布不仅与激光光子能量和外场有关,并且敏感地依赖于金属面与氢负离子之间的距离。这些结果可以应用于许多重要的研究领域,包括超快激光表面催化,更准确的测量电子亲和力和控制低能的光电子和表面的相互作用等。     

氢负离子在磁场和电介质表面附近光剥离的研究

利用闭合轨道理论, 研究了变化的磁场和不同电介质表面对氢负离子光剥离截面的影响, 并推导出了该体系下的光剥离截面公式. 结果发现, 氢负离子的光剥离截面不仅与磁场的强度有关, 而且还与电介质常数有关. 当氢负离子到电介质表面的距离和电介质常数一定时, 体系的光剥离截面中的振荡随磁场的变化而明显变化. 随着磁场强度的 增大, 体系的闭合轨道数目增多, 光剥离截面的振荡越来越复杂. 当氢负离子到电介质表面的距离和磁场强度一定时, 电介质常数的变化对光剥离截面的影响也很重要, 随着电介质常数的增大, 体系的闭合轨道数目增多, 光剥离截面的振荡也变得越来越复杂. 因此, 可以通过改变磁场强度和电解质常数来调整负离子的光剥离截面. 此结果 对于研究负离子体系在表面附近和外场中的光剥离问题具有一定的参考价值.     

氢负离子在变形球面附近的光剥离

利用理论模型成像方法, 对氢负离子在变形球面附近的光剥离进行了研究. 首先, 推导出了光剥离电子通量的计算公式, 然后对电子通量分布和光剥离截面进行了计算.结果表明: 平面效应只在一定范围内对氢负离子的光剥离过程产生影响. 在距离z轴比较近的区域, 球面效应起主要作用, 电子通量分布和光剥离截面与只有球面存在的情况一致, 此时平面效应可以忽略; 距离z轴较远的区域, 平面效应和球面效应共同起作用, 此时变形球面对光剥离过程会产生比较大的影响. 当球面半径和氢负离子到球面之间的距离给定, 随着入射光子的能量增大, 光剥离电子通量的振幅先增大后减小, 然后又慢慢增大, 振荡频率增大.当固定球面与氢负离子之间的距离, 随着球面半径的增大, 光剥离电子的通量趋向于只存在球面的情况.因此, 可以通过改变入射光子能量和球面的半径对氢负离子的光剥离进行调控. 本文的结果对于研究负离子体系在曲面附近的光剥离及光剥离 显微问题的实验研究具有一定的参考价值. 关键词： 理论模型成像方法 光剥离电子通量 光剥离截面 变形球面     

H-在金属面附近光剥离的波包动力学研究

利用波包演化和自关联函数方法对H^-在金属面附近光剥离的波包动力学进行了研究.结果表明,金属面附近光剥离电子的波包演化和回归结构与H^-到金属面的距离、激光脉冲的脉冲宽度和初始动量都有一定的关系.因此,可以通过改变离子表面距离和激光脉冲的参数对光剥离电子的动力学性质进行调控研究.除此之外,光剥离电子的镜像态寿命对波包的演化和自关联函数也会产生一定的影响:考虑镜像态寿命的影响时,随着时间的演化,波包概率密度的振幅逐渐减小,波包整体上有明显的衰减,寿命对波包演化过程中的干涉有削弱的作用;通过对电子波包的自关联函数研究,发现无限长寿命的电子波包有很好的量子回归现象,而当考虑寿命因素后光剥离电子波包随着时间的演化会发生周期性的坍塌和扩散,经过一段时间后,该回归现象消失.本文的理论研究可以为表面附近电子波包动力学的实验研究提供一定的参考价值. 关键词： 波包 演化和回归 自关联函数 金属面     

氢负离子在电介质球面附近的光剥离研究

利用镜像法结合半经典闭合轨道理论,对氢负离子在电介质球面附近的光剥离进行了研究.首先利用镜像法分析了剥离电子在电介质球内的镜像电荷分布情况,然后给出了体系的哈密顿量.通过求解哈密顿正则方程,找到了剥离电子在电介质球面附近运动时的闭合轨道.借助于半经典闭合轨道理论,推导出了体系的光剥离截面,并且对光剥离截面进行了计算和分析.计算结果表明,氢负离子在电介质球面附近的光剥离截面不仅与入射光子的能量有关,而且还与电介质球面的介电常数有关.对于给定的电介质球面,随着入射光子的能量增加,光剥离截面的振荡振幅减小、振荡频率增加.当入射光子的能量增加到某一临界值时,光剥离截面的振荡结构消失.除此之外,随着电介质球面介电常数的增大,光剥离截面的振荡结构变得更加复杂.当电介质常数增大到无穷大时,体系的光剥离截面和氢负离子在金属球面附近的光剥离截面一致.因此,可以通过改变入射光子的能量及电介质球面的介电常数对氢负离子在电介质球面附近的光剥离截面进行调控研究.研究结果对负离子体系在电介质球面附近的光剥离的实验研究可以提供一定的理论指导和参考价值.     

多光束激光干涉光刻图样

利用电磁理论,研究了多光束激光干涉图样的产生原理,结合计算机数值模拟和相关实验结果,分析了干涉图样的影响因素.研究结果表明:多光束激光干涉图样可以看成是多组余弦分布的平行线条纹的叠加;相干光束的偏振方向、入射方向、光束间相位差是干涉图样的重要影响因素,改变这些因素,余弦分布的平行线条纹的振幅、位置、周期和方向发生变化,...     

球面波干涉法测量拉盖尔-高斯光的轨道角动量

采用球面波的拉盖尔-高斯光(LG光)和平面波的基模高斯光干涉的方法 ,可观察到多叶螺旋的干涉图样,螺旋的叶数即是LG光的拓扑荷数,由拓扑荷数可知光子的轨道角动量.利用涡旋相位片产生拓扑荷数1～8的LG光,研究了光强比和偏振条件对干涉图样的影响.为获得高对比度的干涉图样,要求LG光和高斯光的偏振方向相同并且光强基本相等.球面波干涉法用于测量LG光的轨道角动量简单直观,与干涉光强空间分布的细节无关,因此对光强扰动和背景噪声不敏感.     

小振幅低频液体表面波的光学干涉效应的研究

实验上实现了频率为几十赫兹的低频液体表面波的光干涉调制研究,得到了稳定、清晰的干涉图样。理论上对表面波干涉现象进行了分析,得出了条纹分布的解析表达式,较合理的解释了干涉图样的分布现象。该方法适用于低频液体表面波的特性研究,通过分析实验图样,可以对液体的表面张力等特性参数进行研究。     

Photodetachment microscopy of H~- in the magnetic field near different dielectric surfaces

We study the photo-detachment interference patterns of a hydrogen negative ion in the magnetic field near different dielectric surfaces with a semi-classical open orbit theory.We give a clear physical picture describing the photo-detachment of H-in this case.The electron flux distributions are calculated at various dielectric surfaces with unchanged magnetic field strength.It is found that the electron flux distributions of H-are very different in a magnetic field near different dielectric surfaces,namely the dielectric surface has a great influence on the photo-detachment interference pattern of the negative ion.Therefore,the interference pattern in the detached-electron flux distribution can be controlled by changing the dielectric constant.We hope that our studies may guide the future experimental research in photo-detachment microscopy.     

Photodetachment microscopy of a hydrogen negative ion in an electric field near a metal surface

According to the semi-classical theory, we study the photodetachment microscopy of H- in the electric field near a metal surface. During the photodetachment, the electron is photo-detached by a laser and the electron is drawn toward a position-sensitive detector. The electron flux distribution is measured as a function of position. Two classical paths lead the ion to any point in the classically allowed region on the detector, and waves traveling along these paths produce an interference pattern. If the metal surface perpendicular to the electric field is added, we find that the interference pattern is related not only to the electron energy and the electric-field strength, but also to the ion-surface distance. In addition, the laser polarization also has a great influence on the electron flux distribution. We present calculations predicting the interference pattern that may be seen in experiment. We hope that our study can provide a new understanding of the electron flux distribution of negative ions in an external field and surface, and can guide future experimental research on negative ion photo-detachment microscopy.     

Photodetachment microscopy of the hydrogen negative ion in electric field near a metal surface

According to the semi-classical theory, we study the photodetachment microscopy of H^- in the electric field near a metal surface. During the photodetachment, the electron is photo-detached by a laser and the electron is drawn toward a position-sensitive detector. The electron flux distribution is measured as a function of position. Two classical paths lead the ion to any point in the classically allowed region on the detector, and waves traveling along these paths produce an interference pattern. If the metal surface perpendicular to the electric field is added, we find that the interference pattern is related not only to the electron energy and the electric-field strength, but also to the ion--surface distance. Besides, the laser polarization also has a great influence on the electron flux distribution. We present calculations predicting the interference pattern that may be seen in experiment. We hope that our study can provide a new understanding of the electron flux distribution of negative ions in external field and surface, and can guide the future experimental research on the negative ion photo-detachment microscopy.     

Photoionization microscopy of Rydberg hydrogen atom near a dielectric surface

Based on the semiclassical analysis of photoionization microscopy, we study the ionization of the Rydberg hydrogen atom near a dielectric surface. The radial electron probability density distributions on a given detector plane are calculated at different scaled energies and near different dielectric surfaces. We find due to the interference effect of different types of electron trajectories arriving at a given point on the detector plane, oscillatory structures appear in the electron probability density distributions. With the increase in the scaled energy, more types of electron ionization trajectories appear and the oscillatory structure in the electron probability density distributions becomes complex. Besides, the dielectric constant of the dielectric surface can also affect the electron probability density distributions. Since the photoionization microscopy interference pattern recorded on the detector plane reflects the distribution of the square modulus of the transverse component of the electronic wave function, with the recorded interference pattern, we can investigate the ionization dynamics of the Rydberg atom near surfaces clearly. This study provides some reference values for the future experiment research on the photoionization microscopy of the Rydberg atom near dielectric surfaces.     

Electron Flux Distributions in the Photodetachment of H2- in an Electric Field

The electron flux distributions in the photdetachment of a negative hydrogen molecular ion in an electric field have been studied by using the two-center model and the dosed orbit theory. An analytic formula is presented for the electron flux of H2 in the presence of an electric field. The results show that the interference between the two orbits passing through the given spatial point leads to the oscillation in the electron flux distribution. Besides, the interference between the two centers of the H2^- is also very important. The comparison between the electron flux of H2^- in electric field with the result of H^- shows that at the equilibrium distance of two centers in the H2^-, the interference of the two nuclei on the detached electron＇s flux distribution is very strong, while at larger distance of the two centers, the interference effect of the two centers is decreased.     

Photoionization microscopy of Rydberg hydrogen atom in a non-uniform electrical field

In this paper,we investigate the photoionization microscopy of the Rydberg hydrogen atom in a gradient electric field for the first time.The observed oscillatory patterns in the photoionization microscopy are explained within the framework of the semiclassical theory,which can be considered as a manifestation of interference between various electron trajectories arriving at a given point on the detector plane.In contrast with the photoionization microscopy in the uniform electric field,the trajectories of the ionized electron in the gradient electric field will become chaotic.An infinite set of different electron trajectories can arrive at a given point on the detector plane,which makes the interference pattern of the electron probability density distribution extremely complicated.Our calculation results suggest that the oscillatory pattern in the electron probability density distribution depends sensitively on the electric field gradient,the scaled energy and the position of the detector plane.Through our research,we predict that the interference pattern in the electron probability density distribution can be observed in an actual photoionization microscopy experiment once the external electric field strength and the position of the electron detector plane are reasonable.This study provides some references for the future experimental research on the photoionization microscopy of the Rydberg atom in the non-uniform external fields.