共查询到19条相似文献,搜索用时 265 毫秒
1.
用相空间分析方法研究了双金属板间里德堡氢原子的动力学性质.结果表明:标度变换后,其动力学行为敏感地依赖于标度能量 .当标度能量 较小时,体系是近可积的,规则的,随着标度能量的增大,体系是不可积的,运动是混沌的,电子可能被金属表面俘获. 相似文献
2.
里德堡原子具有大的极化率、低的场电离阈值和大的电偶极矩,对外部电磁场十分敏感,可以用来测量电场强度特别是微波电场的强度. 利用里德堡原子的量子干涉效应(电磁诱导透明和Autler-Townes效应)测量微波电场强度的灵敏度远高于传统采用偶极天线测量微波电场的灵敏度. 此外,里德堡原子电场计 可以溯源到标准物理量,不需要额外校准; 采用玻璃探头,对待测电场干扰少; 灵敏度也不依赖于探头的物理尺寸. 同时,该电场计还可以实现对微波电场的偏振方向的测量, 实现亚波长和近场区域电场成像与测量. 通过选择不同的里德堡能级,可以实现1-500 GHz超宽频段范围内微波电场强度的测量. 主要综述基于里德堡原子的电场精密测量研究, 详细介绍了里德堡原子电场计的原理与实验进展, 并简单讨论了其发展方向. 相似文献
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利用双中心原子轨道强耦合方法研究了H+离子与里德堡态的Li(5d)原子碰撞的电荷转移过程,计算了5d电子转移到氢原子各个次壳层的态选择截面及总截面.研究了态选择截面随俘获电子主量子数及角量子数变化的规律,并尝试给出了解析的标度关系;探讨了标度规律随入射粒子能量的变化,分析了高激发态电子电荷转移过程的动力学机制. 相似文献
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利用双中心原子轨道强耦合方法研究了H^+离子与里德堡态的Li(5d)原子碰撞的电荷转移过程,计算了5d电子转移到氢原子各个次壳层的态选择截面及总截面.研究了态选择截面随俘获电子主量子数及角量子数变化的规律,并尝试给出了解析的标度关系;探讨了标度规律随入射粒子能量的变化,分析了高激发态电子电荷转移过程的动力学机制. 相似文献
5.
在室温铯原子蒸气池中, 由铯原子基态、激发态和里德堡态构建了阶梯型三能级系统, 研究了里德堡原子阶梯型三能级系统的电磁感应透明(EIT). 在实现电磁感应透明的基础上, 利用16.9 GHz的射频电场耦合相邻的原子里德堡态, 实现49S1/2→47D3/2的双光子跃迁, 测量了里德堡原子的射频双光子光谱, 观察到了电磁感应透明光谱的分裂, 进一步研究了电场强度对射频双光子光谱的影响. 利用里德堡原子的EIT效应可实现对射频电场幅值和极化的精密测量, 具有潜在的应用前景. 相似文献
6.
利用了氢原子飞渡时间谱实验方法对处于高n主量子数里德堡态的氢原子与氦原子的分子束散射过程进行了高分辨研究.测量了H(n)+He→H(n′)+He散射过程的散射微分截面.实验结果表明,产物主要分布在前向散射方向,在侧向也有一定的分布.在前向和侧向存在大量的振荡结构.同时详细的研究也表明,在上述的散射过程中往前散射的方向上,氢原子里德堡态主量子数n的变化并不是很大.实验结果得到了为理论上精确研究高n主量子数里德堡态的氢原子与氦原子的散射动力学的一套精细的实验数据. 相似文献
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利用散射矩阵理论,结合扩展的半经典闭合轨道理论和多通道量子亏损理论,计算了磁场中高里德堡H2分子的回归谱.该方法使用了两个空间散射矩阵来描述里德堡电子的动力学性质,计算中可以包括所有阶的实散射的作用.回归谱的每一个尖峰对应着一条闭合轨道,新的额外峰是由于弹性散射和非弹性散射所引起的通道内和通道间的轨道组合,进一步证明了体系通道间和通道内的散射具有同等的重要性. 相似文献
9.
利用散射矩阵理论,结合扩展的半经典闭合轨道理论和多通道量子亏损理论,计算了磁场中高里德堡H2分子的回归谱.该方法使用了两个空间散射矩阵来描述里德堡电子的动力学性质,计算中可以包括所有阶的实散射的作用.回归谱的每一个尖峰对应着一条闭合轨道,新的额外峰是由于弹性散射和非弹性散射所引起的通道内和通道间的轨道组合,进一步证明了体系通道间和通道内的散射具有同等的重要性. 相似文献
10.
利用半经典方法研究了平行电磁场中里德堡氢原子的分形自相似现象. 通过研究平行电磁场中里德堡氢原子的逃逸时间和初始出射角间的关系, 发现了逃逸时间图的自相似结构, 并通过研究与图中冰柱对应的逃逸轨道, 得到了自相似结构和逃逸轨道之间的关系, 发现了该类自相似逃逸轨道满足的规律. 进一步研究了标度能量和标度磁场对体系动力学的影响, 表明标度能量和标度磁场均控制体系的分形自相似结构. 当标度能量或标度磁场比较小时, 没有自相似现象, 随着标度能量或标度磁场的增大, 自相似出现, 体系变复杂. 相似文献
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GE Meihua ZHANG Yanhui WANG Dehua DU Mengli & LIN Shenglu . College of Physics Electronics Shandong Normal University Jinan China . Department of Mathematics Physics Shandong Institute of Architecture Engineering Jinan China . Institute of Theoretical Physics Chinese Academy of Sciences Beijing China 《中国科学G辑(英文版)》2005,48(6):667-675
In recent years much attention is focused on the dynamics of Rydberg atom in exter- nal fields. At the same time Rydberg atom near a metal surface plays an important role as a typical theoretical model and produces measurable experimental response[1]. As an interesting model it covers many dynamical effects: instantaneous van der Waals inter- action[2,3], Zeeman-Stark effects and diamagnetic effects in strong fields[4], and so on. Its classical motion is very complex. When the atom-surface i… 相似文献
13.
The dynamical properties of Rydberg hydrogen atom near a metal surface are presented by using the methods of phase space analysis
and closed orbit theory. Transforming the coordinates of the Hamiltonian, we find that the phase space of the system is divided
into vibrational and rotational region. Both the Poincaré surface of section and the closed orbit theory verify the same conclusion
clearly. In this paper we choose the atomic principal quantum number asn=20. The dynamical character of the exited hydrogen atom depends sensitively on the atom-surface distanced. Whend is sufficiently large, the atom-surface potential can be expressed by the traditional van der Waals force and the system
is integrable. Whend becomes smaller, there exists a critical valued
c. Ford>d
c, the system is near-integrable and the motion is regular. While chaotic motion appears ford<d
c, and the system tends to be non-integrable. The trajectories become unstable and the electron might be captured onto the
metal surface. 相似文献
14.
The Ryderberg electronic wave packet dynamics of hydrogen atom near helium surface in an electric field is investigated using the semiclassical method.The autocorrelation function is calculated when the photoionized electron is excited by a short laser pulse for different atom-surface separations.The results show that new recurrences appear because of the helium surface,and the number of recurrent peaks increases with the decrease in atom-surface distance.The new feature is ascribed to the bifurcation of new closed orbits in the classical dynamics of the photoionized electron.Therefore,surface properties have a significant effect on the spectrum of nearby atoms or ions. 相似文献
15.
WANG De-Hua 《理论物理通讯》2008,49(2):467-472
Multielectron to theoretical treatments atoms near a metal surface are essentially more complicated than hydrogen atom with regard By using the semicalssical dosed orbit theory generalized to the multielecton atoms, we study the dynamical properties of the Rydberg lithium atom near a metal surface. The photoabsorption spectra and recurrence spectra of this system have also been calculated. Considering the effect of the ionic core potential of the Rydberg lithium atom, the number of the closed orbits increases, which leads to more peaks in the recurrence spectra than the case of hydrogen atom near a metal surface. This result shows that the core-scattered effects play an important role in nonhydrogenic atoms. This study is a new application of the closed-orbit theory and is of potential experimental interest. 相似文献
16.
We have studied the ionization of Rydberg hydrogen atom near a metal surface with a semiclassical analysis of photoionization microscopy. Interference patterns of the electron radial distribution are calculated at different scaled energies above the classical saddle point and at various atom-surface distances. We find that different types of trajectories contribute predominantly to different manifolds in a certain interference pattern. As the scaled energy increases, the structure of the interference pattern evolves smoothly and more types of trajectories emerge. As the atom approaches the metal surface closer, there are more types of trajectories contributing to the interference pattern as well. When the Rydberg atom comes very close to the metal surface or the scaled energy approaches the zero field ionization energy, the potential induced by the metal surface will make atomic system chaotic. The results also show that atoms near a metal surface exhibit similar properties like the atoms in the parallel electric and magnetic fields. 相似文献
17.
This paper presents the dynamical properties of a Rydberg hydrogen atom between two metal surfaces using phase space analysis methods. The dynamical behaviour of the excited hydrogen atom depends sensitively on the atom--surface distance d. There exists a critical atom--surface distance dc = 1586 a.u. When the atom--surface distance d is larger than the critical distance dc, the image charge potential is less important than the Coulomb potential, the system is near-integrable and the electron motion is regular. As the distance d decreases, the system will tend to be non-integrable and unstable, and the electron might be captured by the metal surfaces. 相似文献
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19.
A. Buchleitner K. Sacha D. Delande J. Zakrzewski 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,5(2):145-157
We present a semiclassical analysis of the dynamics of Rydberg states of atomic hydrogen driven by a resonant microwave field
of linear polarization. The semiclassical quasienergies of the atom in the field are found to be in very good agreement with
the exact quantum solutions. The ionization rates of individual eigenstates of the atom dressed by the field reflect their
quasiclassical dynamics along classical periodic orbits in the near integrable regime, but exhibit a transition to nonspecific
rates when global chaos takes over in phase space. We concentrate both on the principal resonance where the unperturbed Kepler
frequency is equal to the driving field frequency and on the higher primary resonance The latter case allows for the construction of nondispersive wave packets which propagate along Kepler ellipses of intermediate
eccentricity.
Received: 23 June 1998 / Accepted: 10 November
1998 相似文献