离子与原子碰撞中多电子转移的经典描述

讨论了几各地独立电子模型（ＩＥＭ）描述离子与原子碰撞中电子转移的经典模型，即Ｂｏｈｒ－Ｌｉｎｄｈａｒｄｔ模型，过垒模型ＯＢＭ和分子库仑垒模型ＭＣＢＭ。较详细阐述了描述碰撞过程的经典物理图象，着重讨论了ＭＣＢＭ描述的多电子转移过程，分析了几各模型的特点和适用性，最后在考虑了入射离子量子数亏损和出射过程电子束缚能移动的修正后，给出了修正后的ＭＣＢＭ的计算结果，并与Ｎｉｅｈａｕｓ的计算结果玫实验结果进行     

高里德伯态氢原子与氢分子的全量子态分辨的散射动力学研究:费米模型的精确性

文章描述了高里德伯态氢原子与氘分子（D2）散射的近期研究结果。实验研究表明，在高里德伯态氢原子与D2的散射中，非弹性散射和化学反应散射都是重要的。在非弹性散射过程中，氘分子的核自旋是守恒的。反应散射结果说明，高里德伯态氢原子与氘分子的散射动力学和质子与氘分子的散射动力学是非常类似的．这一结果表明，费米的独立碰撞模型在态-态散射动力学的层次上也是正确的。     

四波混频的原理及在高激发态中的应用

原子的高激发态一般包括无数个里德伯态和无数个自电离态.里德伯态指原子中的一个电子被激发到离原子核较远的轨道.处于里德伯态的原子对于磁场或碰撞等外界影响非常敏感,具有很高的反应能力,很容易与微波辐射发生作用.当前在原子分子、光学物理等领域人们所感兴趣的各种实验中常常涉及到里德伯态.     

超冷(36D5/2+6S1/2)里德伯分子的制备及其电偶极矩的测量

里德伯-基态分子由一个里德伯原子和一个基态原子组成,束缚机制是里德伯电子与基态原子的低能电子散射相互作用.理论上,通过低能电子散射Fermi赝势模型,数值计算了铯(36D_5/2+6S_1/2)里德伯-基态分子的绝热势能曲线,提取了里德伯分子的束缚能和平衡核间距等光谱参数.实验上,利用双光子光缔合技术成功制备了散射三重态(^T∑,Triplet)和散射单重态-三重态混合(^S,T∑,Mixed)形成的里德伯-基态分子,获得了里德伯分子的光缔合光谱,测量的势阱深度与理论计算结果相吻合.另外,以散射三重态为例,分析了里德伯分子的光缔合光谱在外加电场中的展宽现象,获得其平均永久电偶极矩|d|为(12.10±1.65) Debye ((4.76±0.65)ea₀),与理论计算结果保持一致.该研究为实验上制备D态里德伯-基态分子提供了可行的实验方案,对理解里德伯分子的光谱特性具有重要意义.     

ECR微波放电氩离子输运过程的研究

建立了电子回旋共振（ＥＣＲ）微波放电等离子体中离子输运过程的蒙特卡罗模型，考虑了离子与中性原子的电荷交换碰撞和弹性碰撞，以及精确依赖于离子能量的电荷交换和动量转移截面，模拟了源于氩气ＥＣＲ微波放电的氩离子向衬底输运的过程，得到与实验报道相符的模拟结果。     

H^＋与He原子碰撞中电子俘获截面的BIB方法计算

用考虑边界修正的一级玻恩畸变波方法（ＢＩＢ）计算了质子与Ｈｅ原子碰撞中的电子俘获面。结果表明在所关心的能区（１００ｋｅＶ～２４００ｋｅＶ）与实验结果较好地一致     

双光子共振非简并四波混频测量钡原子里德伯态碰撞展宽中的伴线研究

研究了采用双光子共振非简并四波混频技术测量原子里德伯态碰撞展宽时出现的伴线现象, 测量了不同缓冲气压下的钡原子里德伯态6snd ¹D₂ (n=16, 22, 36) 的四波混频谱线, 研究了伴线随主量子数n 的变化曲线以及伴线信号强度随缓冲气压压强的变化曲线, 分析了伴线对NFWM谱线的线宽的影响, 发现考虑伴线对四波混频谱线线宽的贡献, 可以对NFWM模型下测量到的碰撞展宽系数进行修正.     

基于联合分离原子模型的电离理论

采用微扰静态(PSS)模型近似处理极化和结合能效应，并引入了相对论效应、能量损失效应和库仑偏转效应修正的ECPSSR理论是描述直接库仑电离过程最成功的理论，但对于低能离子入射时， 其结果明显低于实验值. 采用联合分离原子(USA)模型替代ECPSSR中的PSS模型，考虑分子轨道效应得到了基于USA模型的电离理论——MECUSAR理论. 对部分碰撞系统进行了计算，得到的碰撞截面与实验结果基本符合. 结合OBKN(Oppenheimer-Brinkman-Kramers formulas of Nikolae 关键词： X射线产生截面 离子-原子碰撞 电子俘获     

He（2^3S）,Ne（^3P0,2）与CS2（X↑￣）碰撞的Penning电离反应

利用分子束和化学发光技术，在单次碰撞条件下测量了亚稳态原子Ｈｅ（２＾３Ｓ）与ＣＳ２分子碰撞的Ｐｅｎｎｉｎｇ电离光学光谱。实验得到的ＣＳ２＾＋（Ａ↑￣），ＣＳ２＾＋（Ｂ↑￣）态发光光谱分辨率比目前文献所报到的要好得多，因而我们首次给出了Ｐｅｎｎｉｎｇ电离反应中ＣＳ２＾＋（Ａ↑￣，Ｂ↑￣）态的初生态相对振动布居，其结果与光电子能谱得到的布居明显不同，对这种非Ｆｒａｎｃｋ－Ｃｏｎｄｏｎ跃迁过程本文给予了     

高激发态钠原子与分子碰撞能量转移及分子扩散带辐射的增强效应研究

在钠原子分子混合体系中 ,实验研究了加入缓冲气体对高位态原子分子碰撞能量转移和分子扩散带辐射的增强效应 ;运用瞬态碰撞模型作了理论计算 ,理论结果与实验结果相符合     

70S超冷Cs Rydberg原子的动力学演化

利用双光子激发超冷原子获得70S超冷Cs Rydberg原子, 采用脉冲场电离法使Rydberg原子电离, 并用微通道板测量Rydberg原子的信号. 改变激发光和电离电场脉冲的延迟时间和激发光脉冲的宽度, 研究70S超冷Cs Rydberg原子之间的相互作用和动力学演化过程. 利用黑体辐射导致的态转移和相互作用碰撞电离解释了实验结果,实验结果和理论相一致.     

Experimental Research of Spontaneous Evolution from Ultracold Rydberg Atoms to Plasma

The spontaneous evolution from ultracold Rydberg atoms to plasma is investigated in a caesium MOT by using the method of field ionization. The plasma transferred from atoms in different Rydberg states （n = 22-32） are obtained experimentally. Dependence of the threshold time of evolving to plasma and the threshold number of initial Rydberg atoms on the principal quantum number of initial Rydberg states is studied. The experimental results are in agreement with hot-cold Rydberg-Rydberg atom collision ionization theory.     

Ionization of fast rydberg atoms in longitudinal and transverse electric fields

The main properties of longitudinal and transverse electric field ionizers for fast Rydberg atoms n=21–40 have been investigated. The dispersion and the background due to collisional processes between fast atoms and residual gas molecules have been measured and calculated. The kinetic energy spread of ions formed by field ionization of Rydberg atoms and their trajectories have been calculated. The potassium beam energy was 3.9 keV.     

Processes of decay of Rydberg plasma

The lifetime of a molecule consisting of two Rydberg atoms with respect to electron release is determined from computer simulation of two classical electrons in the field of Coulomb centers. From this, the cross section of the Penning process of collision of two Rydberg atoms with electron release is obtained. The rate constant for ionization of Rydberg atoms is evaluated for the Rydberg plasma within the Thomson model. On the basis of these processes, the kinetics is analyzed for the decay of a Rydberg plasma. Comparison with experimental data shows that these decay processes are responsible for the first stage of the decay of a magnetized and nonmagnetized Rydberg plasma located in a magnetic superconducting trap, whereas other processes become important at a subsequent stage of the plasma evolution. This article was submitted by the authors in English.     

Driving Rydberg-Rydberg transitions from a coplanar microwave waveguide

The coherent interaction between ensembles of helium Rydberg atoms and microwave fields in the vicinity of a solid-state coplanar waveguide is reported. Rydberg-Rydberg transitions, at frequencies between 25 and 38 GHz, have been studied for states with principal quantum numbers in the range 30-35 by selective electric-field ionization. An experimental apparatus cooled to 100 K was used to reduce effects of blackbody radiation. Inhomogeneous, stray electric fields emanating from the surface of the waveguide have been characterized in frequency- and time-resolved measurements and coherence times of the Rydberg atoms on the order of 250 ns have been determined. These results represent a key element in the development of an experimental architecture to interface Rydberg atoms with solid-state devices.     

Rydberg excitation of neutral nitric oxide molecules in strong UV and near-IR laser fields

Rydberg state excitations of neutral nitric oxide molecules are studied in strong ultraviolet(UV) and near-infra-red(IR) laser fields using a linear time-of-flight(TOF) mass spectrometer with the pulsed electronic field ionization method.The yield of Rydberg molecules is measured as a function of laser intensity and ellipticity,and the results in UV laser fields are compared with those in near-IR laser fields.The present study provides the first experimental evidence of neutral Rydberg molecules surviving in a strong laser field.The results indicate that a rescattering-after-tunneling process is the main contribution to the formation of Rydberg molecules in strong near-IR laser fields,while multi-photon excitation may play an important role in the strong UV laser fields.     

Background-free observation of cold antihydrogen with field-ionization analysis of its states

A background-free observation of cold antihydrogen atoms is made using field ionization followed by antiproton storage, a detection method that provides the first experimental information about antihydrogen atomic states. More antihydrogen atoms can be field ionized in an hour than all the antimatter atoms that have been previously reported, and the production rate per incident high energy antiproton is higher than ever observed. The high rate and the high Rydberg states suggest that the antihydrogen is formed via three-body recombination.     

铯47D精细能级超冷里德堡原子自由演化的动力学研究

用连续窄线宽激光器将超冷铯里德堡原子分别激发到47D_3/2, 47D_5/2精细态, 观察了处于里德堡精细态的铯原子向超冷铯等离子体自由演化的过程, 详细对比了不同精细态的铯里德堡原子预电离时间、电离速率以及等离子体的转化效率. 将里德堡原子快速转化为等离子体的过程解释为局域势阱内由预电离产生的电子与里德堡原子的快速碰撞导致的雪崩电离.     

钡准分子共振电离光谱及离化机制研究

本文报道用激光共振电离法获得一个新的钡准分子结构.在染料激光波长扫描范围内观察到钡原子双光子共振跃迁、双光子混合跃迁和钡准分子谱带.我们提出一种用热离子二极管信号特性分析原子和分子里德伯态的离化机制的方法,并以此对钡原子和钡分子的离化通道进行讨论.     

Microwave spectroscopy of the Zeeman effect in Rydberg atoms of sodium

Experimental results of studying the spectrum of the microwave 37P-37S transition of Rydberg sodium atoms in a weak magnetic field (≤7 G) are reported. The populations of the Rydberg states were measured using the method of selective ionization with a pulsed electric field. When the magnetic field was parallel to the ionizing electric field, a good agreement between the calculated and experimental spectral shapes was observed, making it possible to determine the unknown polarization of the microwave radiation. In the case of the orthogonal configuration of the fields, the resonance structure was suppressed in the field ionization signals due to the strong influence of the magnetic field on the electron trajectories in the detection system.