高压类氢原子能量与极化率的另一种计算

 本文采用新的试探波函数，对于关闭在半径为r₀球壳内的类氢原子模型，计算了其能量和极化率随球壳半径r₀和相应压强的变化规律。同文献[1]的结果相比，有明显的改善。     

SU(N)经典杨-Mills方程广义静态球对称解与静态球对称外源的关系

本文讨论了SU（N）经典杨-Mills方程正常广义静态球对称解与静态球对称外源的关系,证明了:（i）可对角化的、不完全均匀的静态球对称外源如果在某球壳r₁2处是N或（N—1）级延展的,则正常广义静态球对称解一定是库仑解;（ii）非狭义球对称的正常广义静态球对称解不可能屏蔽在空间有限区域内。     

高温高压合成立方氮化硼的热力学分析

 从热力学角度计算出了以六角氮化硼为原料、用高压触媒法合成立方氮化硼时所形成稳定的临界晶粒半径r_k的大小,当p=6.0 GPa、T=1 600 ℃时,r_k≈15 nm。分析了r_k的大小与合成温度、压力的关系,以及在给定压力下立方氮化硼晶粒转化率与温度的关系。结果表明：在立方氮化硼稳定区,在相同压力下,r_k随温度的升高而增大;在相同温度下,r_k随压力的升高而减小,r_k越小立方氮化硼晶粒的转化率越高。计算结果与实际合成实验所得结果完全一致。     

SUn群CG系数的一个递推公式

本文证明了,如果采用 Gelfand-Biedenharn 位相约定,则任一 SU_n 群的单态因子（SF）必可分为可导的（SU_nSF）_d 和不可导的（SU_rSF）两类,并且（SU_nSF）_d=（SU_rSF）,n=r十1,r+2,….从而把任一 SU_n 群 C-G 系数的计算归结为少数不可导四子（SU_rSF）的计算。     

高温超导体低温、高压下的物理性质的研究

 在3~20 GPa压力范围内，测量了含氧量较低的YBa₂Cu₃O_7-δ（δ=0.46）单晶压力增强效应（dT_c/dp=4.9KGPa^-1）；YBa₂Cu₃O₇（T_c0=90 K）单晶在压力下临界电流密度随压力变化；外磁场H=30 kO_e时，T_c与磁场、压力关系；压力达16.5 GPa下，Bi₂Sr₂CaCu₂O_x单晶T_c(p)关系（dT_c/dp=-0.4 KGPa^-1）。发现Y系高温超导体的温度压力导数dT_c/dp与T_c0中间呈dT_c/dp=b-mT_c0线性关系（b、m为常数）。结合压力下Y系超导体结构相变和含氧量对T_c影响，分析这类超导体T_c有很强的正压力效应的原因。把实验结果同几种超导电性微观理论模型进行了分析和比较。     

压力对GdoBr:Eu晶场参数的影响

 在室温下测量了GdoBr:Eu的常压和高压荧光谱，光谱范围在13 000~21 500 cm^-1之间，压力至12 GPa。由光谱数据得到了Eu³⁺晶场能级随压力的变化曲线。⁷F_0～5能级随压力的变化规律比较复杂，而⁵D_0~2各能均随压力的升高几乎线性地降低。在基态谱项⁷F的49个状态上进行了晶场拟合计算，所得常压下的5个非零晶场参数分别为：B₀²＝-1 124.0 cm^-1，B₀⁴＝-969.6 cm^-1，B₄⁴＝827.9 cm^-1，B₀⁶＝889.6 cm^-1，B₄⁶＝377.0 cm^-1。高压下的计算结果表明，B₀⁴、B₀⁶这两个晶场参数随压力的增加而增大，B₄⁶随压力的增加而减小，而B₀²、B₄⁴随压力的变化有些起伏。晶场强度在8 GPa以下随压力增加而减小，其后开始变强。     

50 GPa下NiO等温状态方程的高压X光研究

 本文采用在位的（in situ）高压X光衍射方法研究了近50 GPa和室温下三方结构NiO的等温压缩行为，并用Murnaghan状态方程对实验值进行了最小二乘法拟合，得到的NiO室温状态方程的相应参量分别为：B₀=223 GPa，B₀'=4.21。在室温压力范围内没有观察到第一类结构相变。NiO在六方指标下的轴比c/a随压力的变化在实验压力范围内可用c/a=2.450~1.569×10^-3（GPa）近似描述。     

高压对以沸石分子筛基质的Eu（Ⅲ）稀土发光材料荧光光谱影响的研究

 本文研究了高压下无机微孔材料的相转变，并讨论了压力对离子交换的Eu（Ⅲ）NaA和Eu（Ⅲ）NaY两种以沸石分子筛为基质的稀土发光材料发光性质的影响。实验结果表明，对于不同基质材料，压力对Eu（Ⅲ）离子的光谱结构的影响，尤其是对⁵D₀→⁷F₁磁偶极跃迁与⁵D₀→⁷F₂电偶极跃迁强度比（I_m/I_e）的影响十分显著。对于Eu（Ⅲ）NaA样品来说，I_m/I_e值随压力的增加而增加，而对于Eu（Ⅲ）NaY样品，I_m/I_e值随压力的增加而减少。     

τ→πVτ疑难和自旋3/2的τ轻子

本文讨论了τ→πν_r衰变的疑难.和自旋1/2的理论相比,对自旋3/2的重轻子τ和自旋1/2的中微子ν_r,τ→πν_r。道和τ→πν_rν_ll道的比值压低了12/5倍,而其它衰变道没有明显的变动.对自旋3/2重轻子τ在e⁺e^-对撞中的产生也作了讨论.     

CuO在高压下的状态方程、电学性质与相变

 在活塞－圆筒式高压装置上研究了CuO在4.5 GPa内的p-V关系，给出了它的状态方程、格临爱森参数γ₀、体积模量B₀以及B₀的压力导数B₀'。在金刚石压砧装置上，采用我们建立的电阻、电容测量方法研究了CuO在22 GPa内电阻、电容与压力的关系。实验结果表明，CuO的电阻和电容在一些压力下都发生了突然的变化。这些变化可能与CuO内部的电子结构和晶界处的结构状态变化有关。     

强光场下类氢原子的电离能谱

用Ｆｌｏｑｕｅｔ方法迭代求解强光场下类氢原子的Ｓｃｈｒｏｅｄｉｎｇｅｒ方程,较严格地计算线极化光场下的波函数,并用电离边界条件,求出复本征值,最后得到多光子共振电离公式,并与实验比较。     

Static electric dipole polarizability of lithium atoms in Debye plasmas

<正>The static electric dipole polarizabilities of the ground state and n≤3 excited states of a lithium atom embedded in a weekly coupled plasma environment are investigated as a function of the plasma screening radium.The plasma screening of the Coulomb interaction is described by the Debye-H（u|¨）ckel potential and the interaction between the valence electron and the atomic core is described by a model potential.The electron energies and wave functions for both the bound and continuum states are calculated by solving the Schrodinger equation numerically using the symplectic integrator.The oscillator strengths,partial-wave,and total static dipole polarizabilities of the ground state and n≤3 excited states of the lithium atom are calculated.Comparison of present results with those of other authors, when available,is made.The results for the 2s ground state demonstrated that the oscillator strengths and the static dipole polarizabilities from np orbitals do not always increase or decrease with the plasma screening effect increasing, unlike that for hydrogen-like ions,especially for 2s→3p transition there is a zero value for both the oscillator strength and the static dipole polarizability for screening length D = 10.3106a₀,which is associated with the Cooper minima.     

Path Integral Solution for the Coulomb Potential in a Curved Space of Constant Positive Curvature

A new path integral treatment of a hydrogen-like atom in a uniformly curved space with a constant positive curvature is presented. By converting the radial path integral into a path integral for the modified Pöschl-Teller potential with the help of the space-time transformation technique, the radial Green’s function is expressed in closed form, from which the energy spectrum and the corresponding normalized wave functions of the bound states are extracted. In the limit of vanishing curvature, the Green’s function, the energy spectra and the correctly normalized wave functions of bound and scattering states for a standard hydrogen-like atom are found.     

高温等离子体相对论性平均原子模型中的半解析波函数

半解析求解平均原子模型方法充分利用了已知精确波函数的解析性质,通过对平均原子模型中势函数的数值拟合,就得到仅含一个数值因子的半解析波函数以及相应的能量本征值.本文列出了等离子体中相对论性平均原子模型的诸方程,特别注意方程求解技术和程序设计中的一些细节.与完全数值解以及其他类似模型得到的数值解进行的比较表明,在较高温度条件下半解析结果的精度是相当高的,求解的效率也很高.此外还对物理模型中某些缺陷进行了分析.     

Resonance-Radiation Force Exerted by a Circularly Polarized Light on an Atomic Wave Packet

We study the behaviour of an atomic wave packet in a circularly polarized light, and especially give the calculation of the radiative force exerted by the circularly polarized light on the atomic wave packet under the resonance condition. A general method of the calculation is presented and the result is interesting. For example, under the condition that the wave packet is very narrow or/and the interaction is very strong, no matter whether the atom is initially in its ground state or excited state, as time approaches to infinity, the resonance-radiation force exerted by the light on the atom approaches to zero. If the atom is initially in its ground state and excited state with the probability 1/2 respectively, and if the momentum density is a even function, then the resonance-radiation force exerted by the light on the atom is equal to zero.     

Construction of minimizing sequence of multiparticle functions for calculating the spectrum of an atom

A method for calculating the states of a many-electron atom is proposed based on the representation of the wave function of the atom as a linear combination of multideterminant functions. Determinants are constructed from single-particle hydrogen-like functions in which the positive nuclear charge is replaced by a certain effective charge. For each single-particle function, the effective charge is calculated such that to take into account the interaction of a given electron with the spherically symmetric part of the screening charge distribution of remaining electrons. Examples of constructing approximating sequence of functions are given and results of calculations of energies of stationary states of the He and Li atoms are presented.     

Hyperfine interactions of muonium and hydrogen in silicon and diamond: Quantum chemical calculations

The electronic structure of a hydrogen-like atom located at interstitial sites of the silicon and diamond crystals is calculated by the intermediate neglect of differential overlap (INDO) method. Calculations of the electronic g- and hyperfine interaction tensors of the impurity atom are performed. The results obtained are compared with the experimental properties of both “anomalous” muonium and hydrogen centers. It is shown that the most likely model for these centers in silicon and diamond is that in which interstitial neutral hydrogen-like atom locates at the bond-center site.     

Change in the frequency and intensity of the spectral lines of a hydrogen-like atom in the field of a point charge

The changes in the wave functions and the energies of a hydrogen-like atom in the static field of a structureless charged particle are calculated in the asymptotic approximation. The corrections to the energy of states, as well as to the dipole matrix elements of radiative transitions caused by the interaction of the atom with the point charge at long range are calculated using the perturbation theory and the Sturm series for a reduced Coulomb Green’s function in parabolic coordinates. The analytical expressions are derived and tables of numerical values of the coefficients of asymptotic series that determine the corrections to the matrix elements and the intensities of transitions of the Lyman and Balmer series are presented.     

New Exact Solution of Dirac-Coulomb Equation with Exact Boundary Condition

It usually writes the boundary condition of the wave equation in the Coulomb field as a rough form without considering the size of the atomic nucleus. The rough expression brings on that the solutions of the Klein-Gordon equation and the Dirac equation with the Coulomb potential are divergent at the origin of the coordinates, also the virtual energies, when the nuclear charges number Z>137, meaning the original solutions do not satisfy the conditions for determining solution. Any divergences of the wave functions also imply that the probability density of the meson or the electron would rapidly increase when they are closing to the atomic nucleus. What it predicts is not a truth that the atom in ground state would rapidly collapse to the neutron-like. We consider that the atomic nucleus has definite radius and write the exact boundary condition for the hydrogen and hydrogen-like atom, then newly solve the radial Dirac-Coulomb equation and obtain a new exact solution without any mathematical and physical difficulties. Unexpectedly, the K value constructed by Dirac is naturally written in the barrier width or the equivalent radius of the atomic nucleus in solving the Dirac equation with the exact boundary condition, and it is independent of the quantum energy. Without any divergent wave function and the virtual energies, we obtain a new formula of the energy levels that is different from the Dirac formula of the energy levels in the Coulomb field.     

Numerical modeling of the photoionization of Rydberg atoms by the field of an electromagnetic wave

The ionization of excited hydrogen-like atoms in a femtosecond laser pulse is studied by direct numerical integration of the time-dependent Schrödinger equation for a quantum system in the field of an electromagnetic wave. Expressions are obtained for the ionization probability of the system as a function of the parameters of the laser pulse and the initial state of the atom. Ionization suppression is found, confirming the basic premises of the theory of interference stabilization of Rydberg atoms.