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1.
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
2.
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
3.
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
4.
利用相空间分析方法研究了外电场中金属表面附近里德堡氢原子的动力学性质. 结果表明, 体系的动力学性质敏感地依赖于原子与金属表面间的距离和电场强度.通过固定原子与金属表面间的距离, 分析了外加电场作用下里德堡电子的Poincaré 截面和运动轨迹的演化过程. 研究表明: 电场的出现加速了金属表面对电子的吸附, 随着电场强度的增加,体系的动力学性质由原子与金 属表面间的距离控制逐渐变为由电场起主导作用,体系逐渐由不可积变为可积, 电子的运动轨道最终全部变为振动型轨道.
关键词:
Poincaré截面
相空间分析方法
里德堡氢原子 相似文献
5.
Correspondence between classical dynamics and recurrence spectra of Rydberg hydrogen atom near a metal surface 下载免费PDF全文
The chaotic behaviours of the Rydberg hydrogen atom near a metal surface are presented. A numerical comparison of Poincare surfaces of section with recurrence spectra for a few selected scaled energies indicates the correspondence between classical motion and quantum properties of an excited electron. Both results demonstrate that the scaled energy dominates sensitively the dynamical properties of system. There exists a critical scaled energy εc, for ε 〈 εc, the system is near-integrable, and as the decrease of ε the spectrum is gradually rendered regular and finally turns into a pure Coulomb field situation. On the contrary, if ε 〉 εc, with the increase of ε, the system tends to be non-integrable, the ergodic motion in phase space presages that chaotic motion appears, and more and more electrons are adsorbed on the metal surface, thus the spectrum becomes gradually simple. 相似文献
6.
H. Y. Li X. Zhao S. Gao X. Y. Xu H. Zhou S. L. Lin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,49(1):1-6
By using the closed-orbit theory including the effect of Coulomb scattering together with an electrical image potential approach,
the recurrence spectra and the dynamical behaviours of the Rydberg hydrogen atom near a metal surface are presented. Theoretical
analysis and numerical simulation reveal that the impacts of the image potential contributing to the recurrence spectrum are
qualitatively analogous to that of the parallel electrical and magnetic fields on the Rydberg atom. The recurrence spectra
are computed for a few selected scaled energies and the results demonstrate that the scaled energy dominates the dynamical
properties of system. With the increase of the scaled energy e from small to large, the whole trend of spectral structure
is from simple to complex,and then simple. 相似文献
7.
The closed-orbit and the photoabsorption spectra of the Rydberg hydrogen atom between two parallel metallic surfaces 下载免费PDF全文
Using the closed orbit theory, we study the classical motion and calculate the
photoabsorption spectra of Rydberg hydrogen atom between two parallel metallic
surfaces. The results show that the metallic surfaces have a significant effect
on the photoabsorption process. When the distances between the hydrogen atom
and the two metallic surfaces are close to a critical value dc, the number
of the closed orbits is the greatest. When the distance larger or smaller
than dc, the number of the closed orbits decreases and the absorption
spectra are shown to exhibit a damping oscillation. This work is an
interesting new application of closed-orbit theory and is of potential
experimental interest. 相似文献
8.
9.
In this paper we investigate the dynamics of a test particle in
the gravitational field with a quadrupole. By constructing
Poincaré sections for different values of the parameters and
initial conditions, we find a chaotic evolution. From these
Poincaré sections, we further confirm that the chaotic
evolution of the test particle originates from the quadrupole. 相似文献
10.
Dehua Wang Kaiyun Huang Shenglu Lin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(3):699-706
The ionization of Rydberg hydrogen atoms near a metal surface at different scaled energies above the classical saddle point
energy has been discussed by using the semiclassical method. The results show that the atoms ionize by emitting a train of
electron pulses. In order to reveal the chaotic and escape dynamical properties of this system in detail, the sensitive dependence
of the ionization rate upon the scaled energy is discussed. As the scaled energy is close to the saddle point energy, the
ionization process of the hydrogen atom is nearly the same as the case of hydrogen atom in an electric field. There is only
a single pulse of electrons, with an exponentially decaying tail. With the increase of the scaled energy, the ionization rates
are similar to the case of the hydrogen atom in parallel electric and magnetic field, a series of electron pulses appear in
the ionization process. This is caused by classical chaos, which occurs for the metal surface. Our studies also suggest that
the metal surface can play the role of both the electric and the magnetic fields. Our theoretical analysis will be useful
for guiding experimental studies of the ionization of atoms near the metal surface. 相似文献
11.
In the ionisation of Rydberg hydrogen atoms near a metal surface,the electron will escape from the nucleus and arrive at the detector in a time sequence.This probability flux train relies on the initial electron wave packet irradiated by the laser pulse.For simplicity,the laser pulse is usually simplified to a delta function in energy domain,resulting in a sharp initial arrival time with an exponentially decaying tail at the detector.Actually and semiclassically,the initial outgoing wave should be modeled as an ensemble of trajectories propagating away from the atomic core in all directions with a range of launch times and a range of energies.In this case,each pulse in the pulse train is averaged out rather than a sharp profile.We examine how energy and time averaging of the electron wave packet affects the resolution of escaping electron pulses and study the energy dependence of the arrival time for each pulse in the ionisation train.An optimization condition for the laser pulse shape to generate narrow ionisation electron pulse in the train is obtained.The ionisation rates with various excitation energy are calculated also,which show the excitation to higher N Rydberg states will narrow the electron pulse as well. 相似文献
12.
The fractal structure in the ionization dynamics of Rydberg lithium atoms in a static electric field 下载免费PDF全文
The ionization rate of Rydberg lithium atoms in a static
electric field is examined within semiclassical theory which involves
scattering effects off the core. By semiclassical analysis, this
ionization process can be considered as the promoted valence
electrons escaping through the Stark saddle point into the ionization
channels. The resulting escape spectrum of the ejected electrons
demonstrates a remarkable irregular electron pulse train in
time-dependence and a complicated nesting structure with respect to
the initial launching angles. Based on the Poincaré} map and homoclinic
tangle approach, the chaotic behaviour along with its corresponding
fractal self-similar structure of the ionization spectra are
analysed in detail. Our work is significant for understanding the
quantum-classical correspondence. 相似文献
13.
The properties of water in the vicinity of surfaces and under confinement have been extensively studied because of the relevance of a quantitative understanding of many processes that not only take place in biological systems, like cells, membranes and microemulsions, but also in many others such as confined water in rocks, ionic channels and interestellar matter. In this work we perform molecular dynamic calculations of the nanoscopic structure of TIP5P model water confined between two hydrophilic surfaces. We calculate the diffusion coefficients and the atomic density profile of water molecules and polar ions in the system as a function of the number of water molecules per amphiphilic (nW). We also study the dependence of the water layer thickness and the profiles of water dipole orientation with this parameter. 相似文献
14.
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
15.
16.
17.
Using the experimental results obtained for the Dy-Mo(1 1 2) system, we discuss the possibilities and mechanisms of formation of two-dimensional (2D) glasses on metal surfaces. It has been found that in the coverage range 0.07 < θ < 0.58, ordered Dy superstructures formed and observed at T < 400 K are irreversibly destroyed by annealing to higher temperatures and turn into an amorphous (glass) structure on cooling. It is supposed that this conversion is caused by the formation, at T > 400 K, of a Dy-Mo surface alloy in which the rate of Dy surface diffusion is strongly reduced in comparison with its value in the absence of alloying. As a result, the mobility of Dy adatoms becomes too low at the temperatures corresponding to the ordered equilibrium state of the surface, and this state cannot be achieved in reasonable relaxation time. This interpretation is corroborated by the experimental data on substantial suppression of surface diffusion in some coadsorbed layers. Since surface glasses contact with ordered (crystalline) substrates, their structure may have a peculiar character different from that of “conventional” metal glasses. Surface glasses can find a number of applications as rather stable systems that combine low dimensionality, specific electronic structure of their constituents and extremely high density of defects. 相似文献
18.
F. Schlögl 《Journal of statistical physics》1987,46(1-2):135-146
The cumulants of the information loss are discussed as characteristic measures of dynamical chaos. They are extensions of the Liapunov exponent and Kolmogorov entropy, which are given by mean values of the information loss. The most important cumulant of higher than first order is the variance. It is discussed in particular for the logistic map. 相似文献
19.
We present a method for generating fractal surfaces of dimension between two and three. By using the method, five fractal surfaces with dimension 2.262, 2.402, 2.524, 2.631, and 2.771 are created. For each of these surfaces, the reaction of carbon monoxide and oxygen is simulated by using a Monte Carlo method based on the ZGB model [Phys. Rev. Lett. 24 (1986) 2553]. The results show that the catalytic CO oxidation proceeds more efficiently on a surface with higher fractal dimension. It is also found that as the fractal dimension of the surface becomes higher, the first-order kinetic phase transition point (y2) is shifted to a higher partial pressure of CO. This implies that poisoning of the catalyst surface due to CO segregation sets in at a higher CO partial pressure for surfaces with more complexity. 相似文献
20.
Hamilton’s theory of turns for the group SU(2) is exploited to develop a new geometrical representation for polarization optics.
While pure polarization states are represented by points on the Poincaré sphere, linear intensity preserving optical systems
are represented by great circle arcs on another sphere. Composition of systems, and their action on polarization states, are
both reduced to geometrical operations. Several synthesis problems, especially in relation to the Pancharatnam-Berry-Aharonov-Anandan
geometrical phase, are clarified with the new representation. The general relation between the geometrical phase, and the
solid angle on the Poincaré sphere, is established. 相似文献