铷离子-铷原子混合阱飞行时间谱的拟合和仿真模拟

离子-原子混合阱是研究带电粒子-中性粒子低温反应的理想平台,直接甄别反应产物最准确的方法是带电粒子飞行时间谱,飞行时间谱峰的强度、位置(飞行时间)和宽度给出了相应带电粒子的强度和动能(温度)等信息.本文通过分析和模拟铷离子-原子混合阱中的飞行时间谱,获得了不同荷质比的离子绝对强度和温度等信息.具体说,首先使用Gumbel型极值分布函数飞行时间谱的谱峰,获得谱峰强度、位置和宽度等信息.然后对实验建模得到耦合的原子数和总带点离子的速率方程,用这些速率方程拟合实验数据,并结合实验测量到的绝对原子数,获得绝对的离子数强度.由此提供了一种标定探测器(本文使用的是微通道板)的方法.改变电离激光的波长和强度得到的标定因子是一致的,表明了这种方法的可靠性.此外,利用COMSOL Multiphysics模拟实验的飞行时间谱,仿真模拟结果表明离子动能大,谱峰宽度窄.本文对飞行时间谱的强度和宽度分析为冷原子光电离过程的离子-原子反应碰撞和带电粒子温度弛豫奠定了基础.     

Analytical solutions for a doubly driven two-level atom

We have deduced analytical solutions of an energy level diagram of the doubly driven/dressed atom for a two-level atom exposed to a strong near-resonant bichromatic laser field in a special case, i.e., the bichromatic field with frequencies ω1 and ω2, and Rabi frequencies ?1 and ?2, in which the first coupling field of ?1 acts on the bare atomic levels, and then the resulting singly dressed states are driven by the second coupling field of ?2, thus resulting in the doubly dressed atom.We have measured the probe absorption spectra of a doubly driven two-level atom. The system consists of 52S1/2, F= 2 and 5~2P_(3/2), F'= 3 states of ~(87)Rb atoms in a magneto-optical trap(MOT) as well as the cooling/trapping beams and an additional coupling field. As for the spectroscopic properties of the doubly driven two-level atom, theoretical analytical solutions are in general agreement with the experimental spectrum as a whole.     

Momentum Transfer Dependence of Two Types of the Broad Enhancement Phenomena： CO Spectra in the Valence Energy Region

Partial generalized oscillator strength densities of CO molecules related to the excitation of a 5σ or 1π electron are calculated by using multi-scattering self-consistent-field methods.Momentum transfer dependence of two types of the broad enhancement phenomena above the threshold with one-electron character,i.e. shape resonance and non-resonance enhancement,is studied.Our calculations show that the energy position of a non-resonance enhancement is related to the momentum transfer K.Therefore,electron impact based experiments can be used to identify the two types of the broad enhancement phenomena.     

氮气在100 eV以下的绝对振子强度密度

在入射电子能量为2500 eV、能量分辨为100 meV的条件下，得到了氮气在100 eV以下的绝对光学振子强度密度和广义振子强度密度；得到了23 eV和31.4 eV两个超激发态的绝对广义振子强度、并讨论了它们的动量转移依赖特性。     

X-ray absorption spectra of plasmas

In this paper we present a theoretical method to calculate the absorption spectra of hot dense plasmas. Based on our fully relativistic treatment incorporated with the quantum defect theory to handle the huge number of transition arrays from many configurations with high principal quantum number, we can calculate the absorption spectra for any element or multi-element plasmas with little computational efforts. We calculate the absorption spectra of C10H1605 plasmas, which are in good agreement with the experimental spectra. We can then provide diagnostic analysis for plasmas in relevant inertial confinement fusion (lCF) experiments; namely not only to determine plasmas' temperatures and densities, but also to provide the population densities of various ionic stages. Our theoretical method verified by "benchmark experiments" will be a basic tool to provide "precise" opacity data for the ICF research.``     

氪的贝特面

用高分辨快电子能量损失谱方法, 在入射电子能量2.5 keV、激发能范围8-88 eV、动量转移范围0.056-3.56 ato. unit的条件下, 测量了氪的贝特面, 并进一步分析了贝特面的特性.     

氧分子的价壳层光学振子强度研究

在入射电子能量为1500eV、平均散射角为0°、能量分辨为60meV条件下，得到了氧分子在5.7—28.5eV能量区间的光学振子强度密度谱，获得了氧分子E³Σ^-_ｕ的ν′=0，1，2和2³Π_ｕ的ν′=0，1各振动能级的绝对光学振子强度，同时检验了我们的Bethe-Born转换因子外推到低能端的可靠性．将所得结果与前人的工作进行了比     

在时域实验研究扩散诱导的Ramsey压窄

基于Duan-Lukin-Cirac-Zoller(DLCZ)方案,在时域上研究了扩散诱导的Ramsey压窄.以87Rb热原子系综为研究对象,观测到缓冲气体,激光束尺寸和镀石蜡Rb池均可以导致Ramsey压窄现象.实验结果和文献中重复相互作用模型预期的一致.     

氢分子分立区和连续区(11.0—19.0 eV)的光学振子强度研究

利用通道规律,并考虑了转动分布对跃迁峰型的影响,对测量得到的绝对氢分子光吸收谱进行了分析．文中逐个确定了11.0—15.0 eV各振动态的振子强度,并得到了B′¹Σ⁺_u的解离强度．同时,利用多重散射Xα自洽场方法计算了氢分子分立区和连续区（11.0—19.0 eV）的光吸收谱．通过计算值和实验绝对测量值的比较可以说明,在自洽层次,文中理论计算值已能较好地说明本实验. 关键词：     

Relativistic R-matrix studies of photoionization processes of Ar^5＋

The 3s–np photoionization processes of the ground state 2P1/2 and the metastable state 2P3/2 of Ar5＋ are investigated using our recently developed relativistic R-matrix code, where the interactions between the bound states and the continuum states are included. Both resonance positions and the oscillator strengths are in much better agreement with the absolute experimental measurements by Wang et al.[Wang J C, Lu M, Esteves D, Habibi M, Alna’washi G and Phaneuf R A 2007 Phys. Rev. A 75 062712] with a resolution of 80 meV than their theoretical results. The contributions of the two experimental unresolved transitions are distinguished in our calculations, which show that the transitions from the ground state also make significant contributions to some resonances. Our theoretical results are also in good agreement with the measurements for the first resonance with a higher resolution of 20 meV.