碱金属原子双光子共振的能级与光谱

双光子共振增强了碱金属原子的非线性极化率，可以观测到多种非线性光学过程产生的非线性光谱，本文分析了有关的能级分布和光谱特点。     

用原子势模型理论对碱金属原子能级和精细的研究

用最弱受约束电子势模型理论方法，研究了碱金属原子的能级和精细结构的表达式，由实验给出的精细结构间隔数据，得到了一组既适合精细结构计算，又适合能级计算的有效量子数ｎ′和有效电荷数Ｚ′，使二的计算统一在同一组ｎ′和Ｚ′之下。     

锂原子里德伯态能级的精细结构分裂

对锂原子的四体问题的哈密顿算符进行幂级数展开,通过计算原子实的 极化(包括偶极矩,四极矩至八级电极矩)对能级的贡献,同时考虑相对论效应和LS耦合以 及有效势的高阶修正,求得了锂原子里德伯态的能级位移和能级公式。用此公式计算N=5～1 2,L=4～9,J=L±1/2的相关的精细结构位移以及能级间隔,并与有关实验结果进行了比较 。     

碱金属原子多极极化率的解析计算及其应用

通过考虑碱金属原子中的价电子在模型势中的运动, 给出了碱金属原子激发态(包括分立谱和连续谱)的波函数, 导出了碱金属原子的多极动态极化率的计算式中所涉及的矩阵元的解析表达式, 实现了碱金属原子多极动态极化率的解析计算. 作为应用, 利用范德瓦尔斯相互作用系数与动态极化率之间的积分关系, 计算了异核基态碱金属原子间的三体相互作用系数, 将计算结果与此前用稳定变分方法得到的结果进行了比较, 结果显示两者是一致的. 此工作为后续研究激发态碱金属原子间的相互作用奠定了基础.     

关于原子实极化能的计算

本文用经典电磁学方法推得碱金属原子原子实极化能公式，并通过拟合非贯穿轨道实验能级数据求得原子实的电偶极极化率和电四极极化率     

广义拉盖尔多项式及碱金属原子径向方程的求解

将碱金属原子径向方程化为广义拉盖尔多项式微分方程，方便地求出了碱金属原子体系的能级及广义拉盖尔多项式表示的径向波函数。所得结果不仅适用于碱金属原子，也适用于氢原子，类氢离子。     

用原子势模型理论对碱金属原子能级和精细结构的研究

用最弱受约束电子势模型理论方法，研究了碱金属原子的能级和精细结构的表达式．由实验给出的精细结构间隔数据，得到了一组既适合精细结构计算，又适合能级计算的有效量子数ｎ′和有效电荷数Ｚ′，使二者的计算统一在同一组ｎ′和Ｚ′之下．     

碱金属原子价电子轨道贯穿概率的估算

根据玻尔理论和碱金属原子光谱项量子数亏损的实验数据,按照物理量的加权平均计算方法,推导出估算碱金属原子价电子轨道贯穿概率的计算公式.     

钠原子中价电子能级严格解的探讨

对钠原子中的价电子采用原子实极化模型 ,对势能为V(r) =- e2r+τer2 的钠原子 ,用幂级数法 ,严格求解了价电子的定态薛定谔方程 ,得到了束缚态的波函数 ,并由不同角量子数低能级的实验值 ,确定参量τ ,并计算出钠原子的高能级的能量 ,与实验结果比较相一致。     

Calculations on polarization properties of alkali metal atoms using Dirac–Fock plus core polarization method

A semi-empirical atomic structure model method is developed in the framework of a relativistic case. This method starts from Dirac-Fock calculations using B-spline basis set. The core-valence electron correction is then treated in a semiempirical core polarization potential. As an application, the polarization properties of alkali metal atoms, including the static polarizabilities and long-range two-body dispersion coefficients, have been calculated. Our results are in good agreement with the results obtained from ab initio relativistic many-body perturbation method and the available experimental measurements.     

碱金属原子的光激发与光电离

本文研究了碱金属原子在三步激光脉冲作用下的光激发和光电离过程的动力学特性, 重点关注和比较了锂和铯原子的异同. 针对多种激发模式, 本文不但建立了其原子布居数在各个跃迁态的速率方程组, 还给出了各相关态的光激发和光电离过程的解析解. 通过精心设计并选择了特殊情况, 显著简化了解析解的数学表达式, 从而凸显和讨论了其物理内涵. 通过自行编程, 系统地计算和观察了各种激发模式对锂原子的光激发和光电离过程的可能影响, 研究和讨论了电离率随激光参数的变化规律. 在相同激发模式下, 比较和分析了采用两种不同激发路径所导致的各态原子布居率的变化, 凸显了改变原子参数所产生的作用. 探讨了锂和铯原子在类似的激发条件下在电离率方面的差别. 最后, 基于本文的研究结果, 本文指出了优化电离率的多种途径.     

Effects of Ps polarization potentials on Ps total cross-sections of the collisions of positrons with alkali metal atoms and alkaline-earth positive ions

Summary The previous form of the coupled-static approximation applied to the inelastic scattering of positrons by alkali metal atoms is improved by switching on the polarization potentials of the positroniums. The effect of these potentials on the total elastic and positronium formation cross-sections of three different scattering problems (namely the collisions of positrons with lithium, sodium and potassium atoms) is discussed in details. Particularly, we devote our interest to the comparison between the resultant positronium formation cross-sections and those of the inelastic collisions of positrons with berylium, magnesium and calcium positive ions.     

Theoretical calculation of electron-impact resonance excitation of alkali atoms

Total cross-section for electron impact excitation of the resonance levels in Li, Na and K are calculated using the method due to Crothers and McCarroll. The results are compared with other available theoretical and experimental data.     

德拜势中类氢原子能级近似解析式与幂级数求解

对德拜势(Debye)中类氢原子的能级问题采用Rayleigh-Schrdinger微扰展开,给出了能级的一阶修正与原子能级的近似解析式.同时,采用波函数幂级数解法,求得了德拜势下相关的递推关系.在此基础上,利用能量自洽法,求出了相当于二阶修正的德拜势下类氢原子的能级值,并就其计算结果与数值解进行了比较.同时,讨论了相应的临界束缚能态与截断条件.     

On the theoretical calculations of cross-sections for alkali metal atoms reacting with Cl2 and Br2 molecules

Summary An adiabatic capture mechanism is presented to calculate reactive cross-sections for the alkali+Cl₂ and alkali+Br₂ systems. The model is based on empirically constructed potential-energy surfaces and the results are found to be consistent with the experimental values. To speed up publication, the author of this paper has agreed to not receive the proofs for correction.     

Elaborate treatment of the inelastic collisions of positrons with alkali atoms and alkaline-earth positive ions using a restricted coupled-static approximation

Summary We present the results of a very elaborate investigation of the inelastic collisions of positrons with the ground states of the first four alkali atoms (³Li,¹¹Na,¹⁹K and³⁸Rb) and their electronically resemblant alkaline-earth positive ions,i.e. ⁴Be⁺,¹²Mg⁺,²⁰Ca⁺ and³⁹Sr⁺, respectively, using a restricted coupled-static approximation in which the reactance matrices are adjusted to be symmetrical. Our interest is concentrated on the calculation of the total elastic and positronium formation cross-sections and their behaviour in the low-energy region (below 10 eV for the atoms) or the regions above the positronium formation thresholds (when the ions are considered). Our results are the most accurate cross-sections expected from the approximation employed. They reveal, within their limits, the most important characteristics of these cross-sections and provide us with a satisfactory comparison between the main features of positron-atom and positron-ion collisions. Present address.     

硅烯饱和吸附碱金属原子的第一性原理研究

基于密度泛函理论的第一性原理计算, 研究了硅烯饱和吸附碱金属元素原子的稳定性、微观几何结构和电子性质, 并与纯硅烯及其饱和氢化结构进行了对比分析. 研究发现复合物SiX(X=Li, Na, K, Rb)的形成能都是负的, 相对于纯硅烯来说可以稳定存在. Bader电荷分析表明, 电荷从碱金属原子转移至硅原子. 从成键方式来看, 硅烯与氢原子形成共价键, 而与碱金属原子之间形成的键主要是离子性成键, 但还存在部分共价关联成分. 能带计算表明, 锂原子饱和吸附在硅烯形成的复合物SiLi是直接带隙的半导体, 带隙大小为0.34 eV. 其他碱金属饱和吸附在硅烯上形成的复合物都表现为金属性.     

Hyperfine structure of the ground and first excited states in light hydrogen-like atoms and high-precision tests of QED

We consider hyperfine splitting of 1s and, in part, of 2s levels in light hydrogen-like atoms: hydrogen, deuterium, tritium, helium-3 ion, muonium and positronium. We discuss present status of precision theory and experiment for the hfs intervals. We pay a special attention to a specific difference, D ₂₁ = 8E _hfs(2s) - E _hfs(1s), which is known experimentally for hydrogen, deuterium and ³ He ⁺ ion. The difference is weakly affected by the effects of the nuclear structure and thus may be calculated with a high accuracy. We complete a calculation of the fourth order QED contributions to this difference and present here new results on corrections due to the nuclear effects. Our theoretical predictions appear to be in a fair agreement with available experimental data. Comparison of the experimental data with our examination of D₂₁ allows to test the state-dependent sector of theory of the hfs separation of the 1s and 2s levels in the light hydrogen-like atoms up to 10^-8. Received 22 September 2001