Energy dependence of heavy ion collisions 4He + 12C and 12C + 12C elastic scattering

We have studied the transparency of heavy ion collisions at high energies by using Glauber's multiple scattering theory. The good agreement between our calculation and the existing data available strongly emphasizes the dominance of the nucleon-nucleon interaction in nucleus-nucleus collisions at high energies.     

C+ and C++ ion densities scaling in laser plasmas by ultraviolet photoabsorption spectroscopy

Chemical states of Sn in Sn-doped In₂O₃ (ITO) powders and films were studied by Mössbauer spectrometry. From the deconvolution analysis of the spectra it was found that there were 7- and 8-fold coordinated, electrically inactive Sn⁴⁺ species in the host lattice in addition to two electrically active Sn⁴⁺ species. The concentration of the electrically inactive dopants and the carrier densities could be estimated by Mössbauer spectra. The estimated carrier densities for the powders and films were in good agreement with the measured values.     

Photoionization of the excited He atom in Debye plasmas

We present theoretical photoionization cross sections for He 1s2s ¹S and He 1s2p ¹P states in a Debye plasma environment by the complex coordinate rotation method, using a finite L² basis set constructed from one electron Laguerre orbitals. The plasma environment is found to appreciably influence the photoionization cross sections near the ionization threshold. In this regard, the photoionization cross sections of isolated He are compared with other theoretical and experimental results. Our results are in good agreement with the previous results. A new minimum appears in the photoionization cross section curve for the metastable 1s2s ¹S state. Results are given for the S- and D-wave partial photoionization for the excited 1s2p ¹P state.     

温稠密等离子体中Al12+离子的光电离过程

本文采用多组态Dirac-Hartree-Fock方法研究了温稠密等离子体环境中Al12+离子的光电离过程. 等离子体效应采用SM屏蔽势来模拟(Stanton和Murillo在2015年提出). 计算中固定标度温度1.3eV,在强耦合等离子体环境下,研究了等离子体密度对能级,连续态波函数以及光电离截面的影响. 通过与相同等离子体条件下的Debye-Hückel模型势计算的光电离截面对比,发现两种模型对应的结果中未同时出现势形共振峰,这是由于本文采用的屏蔽模型包含等离子体简并、有限温度对动能的梯度修正和量子交换关联效应,对光电离截面的大小和共振结构具有显著影响.     

CN~+离子电子结构和跃迁性质的理论研究

采用多组态参考相互作用方法和AV5Z-DK基组对CN~+离子的两个解离极限C~+(~2P_u)+N(~2D_u)和C~+(~2P_u)+N(~4S_u)下的X~1Σ~+、a~3Π、~1Δ和A~1四个电子态的势能曲线、永久偶极矩和振动能级进行了计算.为保证计算结果的精确性,在计算中考虑了Davidson修正.基于求得的势能曲线,数值求解一维径向薛定谔方程得到了各个电子态的光谱数据,并与实验值和已有的理论值吻合较好.除此之外,对A~1Π→X~1Σ~+和1~1Δ?A1~Π的跃迁性质进行了研究,同时通过跃迁的弗兰克-康登因子及辐射寿命,对CN~+离子激光冷却的可行性进行了分析.     

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.     

Time-dependent perturbation calculations for transition properties of two-electron atoms under Debye plasma

Systematic investigation have been performed for the dynamic polarizabilities, energy levels, oscillator strengths and transition probabilities for the first few members of helium isoelectronic series He, Li⁺,Be²⁺,B³⁺ and C⁴⁺ embedded in the Debye plasma. The effect of plasma is described by introducing an exponential screening (the Debye screening) to the nuclear Coulomb potential. Systematic trend is observed for all the properties under study with respect to increased screening. The ionization potential decreases with an increased screening and the number of bound excited states supported by the Debye screened potential is finite.     

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.     

Atomic structure and transition properties of H-like Al in hot and dense plasmas

The atomic structure and transition properties of H-like Al embedded in hot and dense plasmas are investigated using modified GRASP2 K code. The plasma screening effect on the nucleus is described using the self-consistent field ion sphere model. The effective nuclear potential decreases much more quickly with increasing average free electron density,but increases slightly with increasing electron temperature. The variations of the transition energies, transition probabilities,and oscillator strengths with the free electron density and electron temperature are the same as that of the effective nuclear potential. The results reported in this work agree well with other available theoretical results and are useful for plasma diagnostics.     

Fast-electron-impact ionization process by 3p of hydrogen-like ions in Debye plasmas

The plasma screening of fast-electron-impact-ionization by excited state(3p) of Hydrogen-like ions was investigated in the first Born approximation with a plasma screening length δ varying from 1000a0 to 10a0. The generalized oscillator strength densities showed dramatic changes: some accessional minima occurred along with a remarkable enhancement in certain continuum-energy domains. The double-differential cross sections exhibit not only the same structures as the Bethe surface for moderate and large momentum transfers, but also a broadened enhancement for small momentum transfers.The single-differential cross sections exhibit a near-zero-energy-enhancement and prodigious multiple-shape resonances,depending on the continuum energy and the plasma screening length. These features are analogous to those of the photoionization cross section. These findings, for both types of cross section, can be explained by processes associated with continuum electrons, as long as the potential has a short-range character.     

Effects of covalency on magnetic properties of tetrahedral V4+ ion in garnets

The theory of covalency is applied to the discussion ofg-factors and hyperfine constantsA of a V⁴⁺ ion in tetrahedral sites in garnets Ca₃X₂Ge₃O₁₂ with X=Sc, Al, Lu, In, and NaCa₂. Mg₂V₃O₁₂, Ca₃Sc₂Si₃O₁₂, Sr₃Sc₂Ge₃O₁₂. The site symmetry is S₄. Coefficients in LCAO-MO wave function and the Fermi contact interaction constantx are determined by an iterative procedure from experimental data. The spin-orbit coupling coefficient _d and radial average r ^–3 are deduced from the condition of solvability of four equations: overlap and charge-transfer integrals are also determined.The author is grateful to Dr. P.Novák for many valuable discussions on the subject and Dr. J.Jokl from the Institute of Macromolecular Chemistry of Czechoslovak Academy of Sciences for optical measurements.     

Photodetachment of cold OH- in a multipole ion trap

The absolute photodetachment cross section of OH- anions at a rotational and translational temperature of 170 K is determined by measuring the detachment-induced decay rate of the anions in a multipole radio-frequency ion trap. In comparison with previous results, the obtained cross section shows the importance of the initial rotational-state distribution. Using a tomography scan of the photodetachment laser through the trapped ion cloud, the derived cross section is model-independent and thus features a small systematic uncertainty. The tomography also yields the column density of the OH- anions in the 22-pole ion trap in good agreement with the expected trapping potential of a large field free region bound by steep potential walls.     

Energy levels and transition probabilities in 130Sn

The excited states of ¹³⁰Sn have been studied in the decay of three different isomers of ¹³⁰In. The experimentally determined energy levels and transition probabilities are compared with comprehensive shell-model calculations using the full neutron single-hole configuration space. Additional theoretical and experimental data regarding ¹²⁸Sn are also presented.     

Metal-insulator transition in two- and three-dimensional logarithmic plasmas

We consider the scaling of the mean square dipole moment in a plasma with logarithmic interactions in a two- and three-dimensional systems. In both cases, we establish the existence of a low-temperature regime where the mean square dipole moment does not scale with system size and a high-temperature regime where it does scale with system size. Thus, there is a nonanalytic change in the polarizability of the system as a function of temperature and hence a metal-insulator transition in both cases. The relevance of this transition in three dimensions to quantum phase transitions in (2+1)-dimensional systems is briefly discussed.     

V+20离子的能量和偶极振子强度

用全实加关联方法计算了类锂V+20离子 1s2nl(l=s,p, d;n≤9) 态的电离势和精细结构.依据单通道量子亏损理论, 确定了这三个Rydberg系列的量子数亏损.用这些作为能量的缓变函数的量子亏损,可以实现对任意高激发态(n≥10)的能量的可靠预言.用在计算能量过程中确定的波函数,计算了V+20离子1s22s-1s2np及1s22p-1s2nd (n≤9)跃迁的振子强度.将这些分立态振子强度与单通道量子亏损理论相结合,得到在电离域附近束缚态间的偶极跃迁振子强度以及束缚态-连续态跃迁的振子强度密度,从而将V+20离子的这一重要光谱特性的理论预言外推到整个能域.     

Energy levels and probabilities of radiative transitions in the Kr IX ion

The energy levels of the 3d ⁹4l (l = 1–3) and 3p ⁵3d ¹⁰4l (l = 0, 1) configurations in the Kr IX ion and the probabilities of radiative transitions to the ground state from these excited states have been calculated within the relativistic perturbation theory using a zero-approximation model potential. The results are shown to be stable within this approximation. The well-known problem of anomalously low accuracy of the calculations of some higher lying singlet levels is considered.     

Inhomogeneity tensors of ion microfield in Debye plasma at neutral emitter

A method of calculation of inhomogeneity microfield tensors in Debye plasma, using the Mayer-Mayer cluster expansion, is presented. The octupole inhomogeneity tensor of the ion microfield at a neutral emitter has been calculated for the first time. The quadrupole inhomogeneity tensor of the ion microfield at a neutral emitter has been recalculated. We have performed numerical calculations for plasma consisting of atoms, electrons and singly or doubly charged ions.