Atomic static multipole polarizabilities

Rivail and Rinaldi's scheme to work out the quantum static multipole polarizabilities have been extended to recover convergence in it. Our expressions give exact static multipole polarizabilities for the atomic hydrogen and give reasonable values for He-sequence.     

Dielectronic recombination rate coefficients for hydrogen-like ions

We present rate coefficients for dielectronic recombination for 9 hydrogen-like ions ranging from Ne⁹⁺ to Xe⁵³⁺. In this work, relativistic multi-configuration wavefunctions are used to calculate energy levels as well as the Auger and radiative matrix elements. Results are compared with recent calculations for ions in the helium-like sequence.     

Higher multipole polarizabilities of hadrons from compton scattering amplitudes

Starting with partial wave projections of the Compton scattering invariant amplitudes free of kinematical singularities or zeros, generalized electric and magnetic multipole polarizabilities of spin-0 and $\text{spin}\text{-}\text{1}\text{2}$ hadrons are introduced as threshold limits of the non-Born parts of the corresponding electric and magnetic Compton multipoles. These objects, which enter the higher low-energy theorems for elastic γ-hadron scattering, are shown to be acceptable quantum field theoretical generalizations of the usual static multipolar polarizabilities encountered in classical electrodynamics or non-relativistic quantum mechanics. Using the analyticity properties of the amplitudes, sum rules for the generalized electric and magnetic quadrupole polarizabilities of the proton and the pions are written down and evaluated numerically within the two-particle unitarity approximation.     

Many-body theory for multipole polarizabilities and dispersion forces in helium-helium interactions

Linked cluster many-body perturbation theory has been developed for the calculation of the dynamic quadrupole polarizabilities of the helium atom in its ground state. The polarizabilities have been used to calculate the London dispersion force constants for He-He interactions. The results for the polarizabilities and the van der Waals constants compare very well with other standard values.     

Beam-foil excitation studies of hydrogen-like ions

Ratios of initial populations of foil-excited hydrogen-like ions of He, B, C, N and O have been measured. Combined with earlier results for H obtained by Tielert they show aZ-dependence of the population process and indicate a velocity dependence as well. For the population of thenp-levels (n=2–5) of He⁺ ann-dependence ∞n ^?(3.6±0.4) has been observed.     

类氢离子电离能的计算

在类氢离子电子束缚能一级相对论及电子自旋-轨道作用修正的基础上,考虑到原子核的质量效应及体积效应,计算了类氢离子的电离能,计算结果与文献提供的实验数据相符合,弥补了其他方法的不足.     

Relativistic calculations of electron-impact ionization for highly charged hydrogen-like ions

Electron-impact ionization cross-sections and rate coefficients of the 1s ground state for H-like C, O, Mg, Ar, Fe, Cu, As, Kr, Y, Mo ions with incident electron energies up to 15 times the ionization threshold energy have been systematically calculated by the relativistic distorted-wave Born exchange (DWBE) approximation. The comparison of the result with the experimental data, other theoretical calculations and recommended values shows the very good agreement. The influence from relativistic and the lowest order QED effect in the calculation is discussed. The calculated ionization cross-sections are fitted by empirical formulas. These fits can be readily integrated over a relativistic Maxwellian electron distribution function to obtain rate coefficient for plasma modeling.     

等离子体屏蔽效应对类氢离子束缚态的影响

在Debye屏蔽近似下,通过求解Schrödinger方程,计算了处于等离子体中的类氢离子的束缚态能量本征值与本征函数. 研究了氢原子和类氢Fe25+离子的n l ( n =1-4, l = 0-3)态能级随Debye 屏蔽长度λ的变化规律. 进一步,分析了等离子体屏蔽效应随主量子数n及角量子数l的变化规律, 发现对于给定的l, 等离子体屏蔽效应随主量子数n的增加而增大;对于给定的n,等离子体屏蔽效应随角量子数l 的增大而减小. 最后,我们分析了等离子体环境中类氢等电子序列离子的能级和波函数随屏蔽参数λ的变化规律,发现随着原子序数增大,等离子体屏蔽效应的影响逐渐变小.     

Radiative transition of hydrogen-like ions in quantum plasma

At fusion plasma electron temperature and number density regimes of 1?×?10³–1?×?10⁷?K and 1?×?10²⁸–1?×?10³¹/m³, respectively, the excited states and radiative transition of hydrogen-like ions in fusion plasmas are studied. The results show that quantum plasma model is more suitable to describe the fusion plasma than the Debye screening model. Relativistic correction to bound-state energies of the low-Z hydrogen-like ions is so small that it can be ignored. The transition probability decreases with plasma density, but the transition probabilities have the same order of magnitude in the same number density regime.     

Determination of static dipole polarizabilities of Yb atom

We determine the static values of the scalar and tensor dipole polarizabilities of the ground, 6s6p~3P_0~o, and 6s6p~3P_1~o states of the Yb atom. These results can be useful in many experiments undertaken using this atom. We employed a combined configuration interaction(CI) method and a second-order many-body perturbation theory(MBPT) to evaluate energies and electric dipole(E1) matrix elements of many low-lying excited states of the above atom. These values are compared with the other available theoretical calculations and experimental values. By combining these E1 matrix elements with the experimental excitation energies, we estimate the dominant valence correlation contributions to the dipole polarizabilities of the above states. The core contribution is obtained from the finite field approach. We also compare these values with the other theoretical results as there are no precise experimental values that are available for these properties.     

Dynamic multipole polarizabilities of Li and Na atoms interacting with Debye potentials

The effects of Debye potentials on the dynamic multipole polarizabilities of Li and Na atoms are investigated using the symplectic algorithm. Frequency-dependent multipole polarizabilities of Li(2s ²S) and Na(3s ²S) are reported in terms of scaled number density of the plasma electrons for arbitrary plasma temperature.     

Higher multipole polarizabilities of hadrons from compton scattering amplitudes (II)

A procedure to derive closed form-sum rules for the hadron generalized electric and magnetic polarizabilities of any multipolar order is presented and discussed. The obtained results complete our previous analysis and may prove useful for a better understanding of the polarizability properties of a spin 0 or $\text{1}\text{2}$ hadron in as far as these show themselves in low energy elastic photon-hadron interactions.     

The uncertainties in radial position and radial momentum of an electron in the non-relativistic hydrogen-like atom

Similar to the case of a simple harmonic oscillator, an increase in azimuthal quantum number l will result in simultaneous decrease in both the uncertainty in radial position and the uncertainty in radial momentum for the same principal quantum number n in the non-relativistic hydrogen-like atom. Thus, in some cases of hydrogen-like atom and in the case of a simple harmonic oscillator, the more precisely the position is determined, the more precisely the momentum is known in that instant, and vice versa.     

Relativistic calculations of one-photon transition probabilities in hydrogen-like ions

The one-photon transition probabilities in hydrogen-like ions are calculated for nuclear charge numbers in the range 1 ≤ Z ≤ 100. The calculations are performed in the framework of the relativistic Dirac’s theory for the states with the principal quantum numbers n = 2,3, 4. The finite nuclear size effect is taken into account. The role of the quantum electrodynamics (QED) and nuclear recoil corrections is also considered.     

Electronic polarizabilities of ions in transition metal oxides

A method for evaluating the electronic polarizabilities from ionic radii in transition metal oxides has been suggested. The ionic radii used in the present calculations are those deduced from the electron density measurements. The calculated polarizabilities agree closely with the experimental values obtained from the electronic dielectric constant.     

Dipole polarizabilities of plasma-embedded Ps and H ions

We have investigated the effect of weakly coupled hot plasmas on the dipole polarizabilities of positronium negative ion and hydrogen negative ion. The plasma effect is taken care of by employing a screened Coulomb (Yukawa) potential of Debye type, and highly correlated exponential wave functions are used. Dipole polarizabilities for various screening parameters are reported.