Y. Z. Qu

The generalized oscillator strengths of hydrogenlike ions in Debye plasmas

Plasma screening effects on the high-energy electron-impact excitation of hydrogenlike ions are investigated under the first Born approximation. The screening interactions are described by the Debye–Huckel model, and the wave functions are calculated numerically in a symplectic scheme. The generalized oscillator strengths (GOS) for transitions between the principal quantum number n⩽3 bound states are presented, and as an example, the scaled differential cross sections and total cross sections for 1s→2s and 2p and 2s→2p transitions are also given. It is found that the plasma screening interactions reduce the GOS for transitions between the states with different n and increase the GOS between the states with same n. The differential and total cross sections are decreased as the screening interactions increase.

Plasma effect on fast-electron-impact-ionization from 2p state of hydrogen-like ions

Plasma effects on the high-energy electron-impact ionization process from 2p orbital of Hydrogen-like ions embedded in weakly coupled plasmas are investigated in the first Born approximation. The plasma screening of the Coulomb interaction between charged particles is represented by the Debye Huckel model. The screening of Coulomb interactions decreases the ionization energies and varies the wave functions for not only the bound orbital but also the continuum; the number of the summation for the angular-momentum states in the generalized oscillator strength densities is reduced with the plasma screening stronger when the ratio of e/I2p (I2p is the ionization energy of 2p state and e is the energy of the continuum electron) is kept, and then the contribution from the lower-angular-momentum states dominates the generalized oscillator strength densities, so the threshold phenomenon in the generalized oscillator strength densities and the double differential cross sections are remarkable: The accessional mini...

Multiconfiguration Dirac-Hartree-Fock calculations of excitation energies, oscillator strengths, and hyperfine structure constants for low-lying levels of Sm I

The multi-configuration Dirac-Hartree-Fock method was employed to calculate the total and excitation energies, oscillator strengths and hyperfine structure constants for low-lying levels of Sm I. In the first-order perturbation approximation, we systematically analyzed correlation effects from each electrons and electron pairs. It was found that the core correlations are of importance for physical quantities concerned. Based on the analysis, the important configuration state wave functions were selected to constitute atomic state wave functions. By using this computational model, our excitation energies, oscillator strengths, and hyperfine structure constants are in better agreement with experimental values than earlier theoretical works.

Ab initio many-electron study for the low-lying states of the alkali hydride cations in the adiabatic representation

An ab initio multireference single- and double-excitation configuration interaction (CI) study is carried out for the ground and excited electronic states of alkali-hydride cations (LiH(+), NaH(+), KH(+), RbH(+), and CsH(+)). For all alkali-metal atoms, the first inner-shell and valence electrons (nine active electrons, three for Li) are considered explicitly in the ab initio self-consistent-field and CI calculations. The adiabatic potential energy curves, radial and rotational couplings are calculated and presented. Short-range (∼3 a.u.) potential wells produced by the excitation of the inner-shell electrons are found. The depths of the inner potential wells are much greater than those of the outer wells for the CsH(+) system. The computed spectroscopic constants for the long-range potential well of the 2 (2)Σ(+) state are very close to the available theoretical and experimental data. The electronic states of alkali-hydrogen cations are also compared with each other, it is found that the positions of the potential wells shift to larger internuclear distances gradually, and the depths of these potential wells become greater with increasing alkali-metal atomic number. The relationships between structures of the radial coupling matrix elements and the avoiding crossings of the potential curves are analyzed. From NaH(+) to CsH(+), radial coupling matrix elements display more and more complex structures due to the gradual decrease of energy separations for avoided crossings. Finally, the behavior of some rotational couplings is also shown.

The theoretical studies on the electron-impact single ionization of Se3+

We have performed fully relatively level-to-level distorted-wave (LLDW) calculations for both direct ionization (DI) and excitation autoionization (EA) of ground state Se3+ ion using the flexible atomic code (FAC). Large EA contributions come from the excitations 4p to nl and 3d to nl. Our calculated total DI+EA cross section have been compared with the recent experimental results. It suggests that the contributions of resonace-excitation double-autoionization process (REDA) to electron impact single ionization of Se3+ at the near threshold are more than 25%.

Low-energy charge transfer in collisions of He2+ with H in a Debye plasma

Charge transfer in collisions of {alpha} particles with ground-state H embedded in a Debye plasma is studied in the low-energy region from 10{sup -4} eV to 5 keV. The screened Coulomb interaction is described by the Debye-Hueckel potential. The relevant molecular potentials and coupling matrix elements are obtained using a modified multireference single-and double-excitation configuration interaction package. Total and state-selective cross sections in the nonradiative charge-transfer collisions from 60 eV to 5 keV are calculated using the quantum-mechanical molecular-orbital close-coupling method. Both optical-potential and semiclassical methods have been used in the investigation of the radiative charge transfer from 10{sup -4} to 1 eV and 1 to 10{sup 2} eV, respectively. The total cross sections for the no-screening case are in good agreement with the existing data. The effects of the screened Coulomb potential on the electron-capture cross sections are discussed.

Radiative charge transfer and radiative association in He+ + Ne collisions

A fully quantum-mechanical approach is utilized to study the collision process of He{sup +} with neutral neon, and the radiative charge transfer (RCT) and radiative association (RA) cross sections are presented in the energy range from 0.08 meV to 1 eV, while the optical potential and semiclassical methods are adopted to calculate the total radiative decay cross sections for energies from 0.08 meV to 5 keV. The potential energy curves and dipole transition matrix elements are obtained by an ab initio multireference configuration interaction package. For the related three lowest X {sup 2{Sigma}+}, A {sup 2{Pi}}, and B {sup 2{Sigma}+} states, the spectroscopic data are in good agreement with other theoretical calculations and experimental measurements. Our results indicate that the RCT cross section is much larger than the nonradiative charge transfer cross section for collision energy E 40 eV, the nonradiative process becomes dominant. Especially, we found that in the present collision system the RA process is more important than the RCT process when E < 1 meV. The RCT and RA rate coefficients are also given for temperatures from 1 to 4 x10{sup 3} K.

Relativistic R-matrix calculations for L-shell photoionization cross sections of C II

Sabri Bouchoucha, Kamel Alioua, Moncef Bouledroua Chin. Phys. B . 2017, 26(7): 073202. doi: 10.1088/1674-1056/26/7/073202 Low-lying electronic states of CuN calculated by MRCI method Shu-Dong Zhang(张树东), Chao Liu(刘超) Chin. Phys. B . 2016, 25(10): 103103. doi: 10.1088/1674-1056/25/10/103103 Influence of the interaction volume on the kinetic energy resolution of a velocity map imaging spectrometer Peng Zhang(张鹏), Zheng-Peng Feng(冯正鹏), Si-Qiang Luo(罗四强), Zhe Wang(王哲) Chin. Phys. B . 2016, 25(3): 033202. doi: 10.1088/1674-1056/25/3/033202 An ab initio investigation of the low-lying electronic states of BeH

Hyperfine induced transition probabilities from

The hyperfine induced

4{f}^{14}5s5p{}^{3}{{\rm{P}}}_{0,2}^{o}

4f^{14}5s5p~^3\mathrm{P}^o_{0,2}~-~4f^{14}5s^2~^1\mathrm{S}_0