里德堡钠原子抗磁谱的模型势计算

用B样条基组展开方法结合模型势计算了里德堡钠原子抗磁谱和相应的振子强度谱.径向和角向均采用高阶B样条基组.计算结果与已有的R-矩阵和多通道量子亏损理论相结合(R-matrix MQDT)法及其他理论计算结果作了比较,几种理论结果在我们所研究的能区内符合得非常好.本文方法较R-ma-trix MQDT法简单,易于推广到交叉电磁场中里德堡原子的精确谱的计算中.     

平行电磁场中的Rydberg锂原子吸收谱的模型势计算

用B样条基组展开方法结合模型势计算了Rydberg锂原子在平行电磁场下的振子强度谱. 径向和角向均采用高阶Ｂ样条基组.计算结果与已有的实验结果符合得很好.利用分波分析法,对部分谱线的振子强度的强弱进行了分析. 本文方法简单有效，易于推广到交叉电磁场中Rydberg原子的精确谱的计算. 关键词： B样条 能谱 振子强度 平行电磁场 Rydberg原子     

囚禁于巴基球内的钠原子里德堡特性

通过非线性变换和特殊设计结点的B样条函数方法研究计算了囚禁于巴基球内的钠原子的里德堡能级结构和振子强度.计算结果表明,巴基球等效势阱深度可以有选择的影响和改变里德堡原子的特性.     

囚禁于巴基球内的原子的里德堡特性

通过非线性变换和特殊设计结点的B样条函数研究计算了囚禁于巴基球内的氢原子里德堡能级结构和振子强度 .结果表明 ,巴基球等效势阱深度可以有选择的影响和改变里德堡原子的特性 ;囚禁原子拥有很多自由原子所没有的奇特性质. Rydberg energy levels and oscillator strength of endohedrally confined H atom have been calculated by using a nonlinear algebraic mapping technique and B-spline method.The boundary conditions are conveniently satisfied with a specially designing knot sequence.Our results show that endohedral can selectively alter the properties and energy levels of Rydberg atoms, and such atoms possess some properties and behaviours which are not previously met or studied in free systems.     

氢原子Rydberg态抗磁谱的高阶B-spline基组计算

在球坐标下采用基组展开方法计算了均匀磁场中的氢原子高Rydberg态能谱和振子强度谱.径向和角向均采用高阶B样条基组. 径向采用B样条基组能很好地描述束缚态与连续态的耦合；角向采用B样条基组有效地减少了基组维数，计算效率得到大幅度提高. 用上述方法计算了磁场中氢原子Rydberg态-40cm^-1到零场电离阈的高精度抗磁谱并与已有理论和实验结果作了比较. 该方法适用于低于离化阈的所有能区的精确谱计算并易于推广到非氢原子、交叉场中的原子以及高于离化阈的正能区光谱的计算. 关键词： 氢原子 B样条基组 能谱 振子强度谱     

用B样条函数方法研究碱金属原子里德堡态在静电场中的性质

由原子的模型势出发,利用B样条函数方法研究了钾和铯原子的里德堡态在静电场中Stark态能级反交叉位置以及微波场中钾原子的多光子共振吸收谱.研究表明我们的结果与实验和其他理论结果符合得很好.     

Calculation of Excited States of He Atoms in a Strong Magnetic Field

A recently developed B-spline algorithm is extended and utilized to calculate excited states of He atoms in the presence of strong magnetic fields. Binding energies are presented for He in the five excited atomic states 2¹0⁺, 1¹0^-, 2¹0^-, 1¹(-1)⁺, and 2¹(-1)⁺ with magnetic field strength ranging from 0.0001 to 10 a.u. The obtained energies are compared with available theoretical data, and found to be in good agreement. We investigate influence of magnetic fields on atomic structures of multielectron atoms, and illustrate that how electron probability density distributions change with increasing magnetic field strength. The current approach is directly applicable to simulations of discrete spectra for He atoms in the atmospheres of magnetized white dwarf stars.     

THE POTENTIAL MODEL INVESTIGATION OF STARK EFFECT IN CAESIUM RYDBERG STATE ATOMS AND COMPARISON WITH EXPERIMENT

The potential model method for computation of Stark structure of Cs Rydberg states atoms and oscillator strength is described, for external electric fields varying from 0 to 600V/cm. Anticrossing, l-mixing and n-mixing phenomena are observed clearly from the map of Stark. Corresponding experiment is performed under the same condition, and the two results are in good agreement with each other within the experimental uncertainty.     

Semiclassical calculation of the recurrence spectra of He Rydberg atom in perpendicular electric and magnetic fields

Closed orbit theory is a semiclassical technique for explaining the spectra of Rydberg atoms in external fields. By developing the closed orbit theory from two degrees of freedom to three non-separable degrees of freedom, we calculated the recurrence spectra of He Rydberg atom in perpendicular electric and magnetic fields. The closed orbits in the corresponding classical system have also been obtained. Fourier transformed spectra of He atoms have allowed direct comparison between the resonance peaks and the scaled action values of closed orbits, whereas the nonhydrogenic resonance can be explained in terms of the new orbits created by the core scattering. The semiclassical result is in good agreement with the quantum spectra, which suggests that our method is correct.     

Beyond nearest-neighbor spacing distributions: A new indicator for core-induced chaos

We present a method for the statistical analysis of quantum spectra which goes beyond the standard nearest-neighbor spacing distribution. The method exploits a peculiar correlation of oscillator strength and level spacing distributions. For diamagnetic Rydberg spectra we demonstrate that core-induced chaos and generic chaos can be distinguished in an experimentally accessible regime far below the semiclassical limit and with already a few hundred lines per spectrum. We present two hypotheses for a generalization of our findings.     

Sodium atom in strong magnetic fields：a pseudospectral approach

Energies and wavefunctions of low-lying states and Rydberg states for the sodium atom in uniform magnetic fields varying from 0 to 10^5T are calculated using a pseudospectral approach with a model potential in spherical coordinates. The energies are comparable with experimental results as well as those obtained by other calculations. The spectra of oscillator strength are worked out. The evolution of them with the magnetic field is shown.     

Population coherent control of a Rydberg sodium atom in a microwave field

The B-spline expansion technique and the time-dependent multilevel approach (TDMA) are used to study the interaction between a microwave field and sodium atoms. The Rydberg sodium atom energy levels of p states in zero field are calculated, and the results are in good agreement with the other theoretical ones. The time evolutions during the population transfers of the five states from n = 75 to n = 79 in different microwave fields are obtained. The results show that the coherent control of the population transfer from the lower states to the higher ones can be accomplished by optimizing the microwave pulse parameters.     

基于Rydberg原子的超宽频带射频传感器

Rydberg原子具有极大的极化率和微波跃迁偶极矩,对外界电磁场非常敏感,可实现基于Rydberg原子的超宽频带射频电场的高分辨高灵敏测量.通过Rydberg原子的全光学无损的电磁感应透明探测手段,可以实现基于原子的快速免校准宽频带(0.01-1000 GHz)外电场的精密测量.对于频率大于1 GHz的微波场,由微波场耦合相邻Rydberg能级形成的Autler-Townes分裂进行测量;而对于频率小于1 GHz的长波射频场,由Rydberg能级的射频边带能级进行测量.这种方法是基于原子能级参数,可溯源到基本物理常量,不依赖于外界参考;且对电场无干扰,易于实现微型化和集成化,具有广泛的应用前景.本文主要综述了基于Rydberg原子的外电场测量的最新研究进展,重点介绍长波长射频场的测量,包括电场强度、频率以及极化方向的测量,详细介绍了其测量原理和探测灵敏度,并讨论了其应用前景及未来发展方向.     

用B-样条函数研究静电场中锂原子里德伯态的性质

用B-样条函数展开方法,结合原子的单电子势模型研究了静电场中锂原子里德伯态的性质. 所得到的Stark能级图、反交叉位置、反交叉宽度以及振子强度与已有的实验和其他理论结果符合得很好. 表明该方法是一种有效的研究静电场中碱金属原子性质的方法. 最后,在数值上研究了锂原子里德伯态振子强度谱随静电场场强的演化特征. 关键词： B-样条函数 振子强度 反交叉位置 反交叉宽度     

用B-样条函数研究静电场中锂原子里德伯态的性质

用B-样条函数展开方法，结合原子的单电子势模型研究了静电场中锂原子里德伯态的性质. 所得到的Stark能级图、反交叉位置、反交叉宽度以及振子强度与已有的实验和其他理论结果符合得很好. 表明该方法是一种有效的研究静电场中碱金属原子性质的方法. 最后，在数值上研究了锂原子里德伯态振子强度谱随静电场场强的演化特征.     

Real-Space Wave-Packet Propagation Method： Application to Photoabsorption Processes of Hydrogen Atoms

A theoretical method of real-space wave-packet propagations with patch meshes is used to study the photoabsorption processes of hydrogen atoms. A complete spectrum of optical oscillator strength densities for transitions from the ls state to the final states of p channel including infinite Rydberg series and adjacent continuum states is calculated. The calculation result agrees well with the analytical solution of hydrogen atoms. The present proposed method should be very useful in applications of various quantum dynamical processes.     

静电场中铷原子里德堡态反交叉位置和宽度的计算

用碱金属原子的模型势结合B-样条函数展开方法研究了静电场中铷原子里德堡态的能级结构特点,计算了铷原子主量子数n由16到25之间的(n 3)s和(n,k)态间的Stark能级反交叉位置和宽度,得到了与实验相一致的结果,并给出了计算铷原子在静电场中高里德堡态能级反交叉位置的经验公式.     

Observation of the Dipole Blockade Effect in Detecting Rydberg Atoms by the Selective Field Ionization Method

The dipole blockade effect at laser excitation of mesoscopic ensembles of Rydberg atoms lies in the fact that the excitation of one atom to a Rydberg state blocks the excitation of other atoms due to the shift in the collective energy levels of interacting Rydberg atoms. It is used to obtain the entangled qubit states based on single neutral atoms in optical traps. In this paper, we present our experimental results on the observation of the dipole blockade for mesoscopic ensembles of 1–5 atoms when they are detected by the selective field ionization method. We have investigated the spectra of the three-photon laser excitation 5S1/2 → 5P3/2 → 6S1/2 → nP3/2 of cold Rydberg Rb atoms in a magneto-optical trap. We have found that for mesoscopic ensembles this method allows only a partial dipole blockage to be observed. This is most likely related to the presence of parasitic electric fields reducing the interaction energy of Rydberg atoms, the decrease in the probability of detecting high states, and the strong angular dependence of the interaction energy of Rydberg atoms in a single interaction volume.     

Semiclassical Calculation of Recurrence Spectra of Li Rydberg Atom in Crossed Electric and Magnetic Field

Closed-orbit theory is a semiclassical technique for explaining the spectra of Rydberg atoms in external fields. Using the dosed-orblt theory and classical perturbation theory, we calculate the scaled recurrence spectra of Lithium atom in magnetic field plus a weak perpendicular electric field. The results show when the crossed electric field is added, the recurrence spectra are weakened greatly. As the scaled electric field f increases, the peaks of the recurrence spectra lose strength. Some recurrences are very sensitive and fall off rapidly as f increases, others persist till much higher f. As the electric field is stronger, some of the peaks revive. This phenomenon, caused by the interference among the electron waves that return to the nucleus, can be computed from the azimuthal dependence of the classical closed orbits.     

Superexcited states of carbon monoxide studied by fast-electron impact

Absolute optical oscillator strength density and double differential cross section spectra of CO below 120 eV are determined by fast electron impact. Some peaks above the first ionization threshold stand out as the momentum transfer square K2 increases. The doubly excited Rydberg states converging to C 2∑^＋, D ^2∏, and F ^2∏ states of CO^＋, respectively, are confirmed in our spectra. Another peak at around 32eV is assigned to the transition of （3σ）^-1（2π）^1^1∏←X^1∑^＋.