Dong Chen-Zhong

A Semi-Quantitative Analysis of Essential Micronutrient in Folium Lycii Using Laser-Induced Breakdown Spectroscopy Technique

In this paper, the capabilities of laser-induced break down spectroscopy (LIBS) for rapid analysis to multi-component plant are illustrated using a 1064 nm laser focused onto the surface of folium lycii. Based on homogeneous plasma assumption, nine of essential micronutrients in folium lycii are identified. Using Saha equation and Boltzmann plot method electron density and plasma temperature are obtained, and the irrelative concentration (Ca, Mg, Al, Si, Ti, Na, K, Li, and Sr) are obtained employing a semi-quantitative method.

Polarization of M2 Line Emitted Following Electron-Impact Excitation of Beryllium-Like Ions

Detailed calculations are carried out for the electron-impact excitation cross sections from the ground state to the individual magnetic sublevels of the 1s2s22p3/2J = 2 excited state of highly-charged beryllium-like ions by using a fully relativistic distorted-wave (RDW) method. The contributions of the Breit interaction to the linear polarization of the 1s2s22p3/2 J = 2 →1s22s2 J = 0 magnetic quadrupole (M2) line are investigated systematically for the beryllium isoelectronic sequence with 42 ≤ Z ≤ 92. It is found that the Breit interaction depolarizes significantly the linear polarization of the M2 fluorescence radiation and that these depolarization effects increase as the incident electron energy and/or the atomic number is enlarged.

Relativistic Distorted-Wave Calculations of Electron Impact Excitation Cross Sections of Be-Like C2+ Ions

A fully relativistic distorted-wave program is developed based on the Grasp92 and Ratip packages to calculate electron impact excitation (EIE) cross sections. As a first application of the program, the EIE cross sections of Be-like C2+ ions from the metastable 1s22s2p 3P to 1s22p2 3P excitation and the inner-shell excitations are calculated systematically. Meanwhile, the correlation effects of target states are discussed. It is found that the correlation effects play an important role in the low energy EIE cross sections. An excellent agreement is found when the results are compared with previous calculations and recent measurements.

Interference Effects in Hyperfine Induced 2s2p 3P0, 3P2 → 2s2 1S0 Transitions of Be-like Ions

The hyperfine induced 2s2p P0, P2 → 2s 2 S0 E1 transition probabilities of Be-like ions were calculated using grasp2K based on multi-configuration Dirac-Fock method and HFST packages. It was found that the hyperfine quenching rates are strongly affected by the interference for low-Z Be-like ions, especially for 2s2p P0 → 2s2 S0 transition. In particular, the trends of interference effects with atomic number Z in such two transitions are not monotone. The strongest interference effect occurs near Z = 7 for 2s2p P0 → 2s 2 S0 E1 transition, and near Z = 9 for 2s2p P2 → 2s 2 S0 E1 transition. PACS: 31.30.Gs; 31.15.V-; 31.15.ag. key words: Hyperfine induced transition; Hyperfine spectroscopy; Interference effect; Be-like ions.In this paper, we explored the characteristics of the interference effects between perturbative states in hyperfine induced 2s2p 3P0, 3P2 → 2s21S0 transitions of Be-like ions. It was found that the interference effects non-monotonically change with increasing atomic number Z in these two transitions. The strongest interference effect is near Z = 9 for 2s2p 3P0 → 2s21S0 transition and near Z = 7 for the other.

Deposition of Polymer Thin Film Using an Atmospheric Pressure Micro-Plasma Driven by Dual-Frequency Excitation

Polymer thin film deposition using an atmospheric pressure micro-plasma jet driven by dual-frequency excitations is described in this paper. The discharge process was operated with a mixture of argon (6 slm) and a small amount of acetone (0-2100 ppm). Plasma composition was measured by optical emission spectroscopy (OES). In addition to a large number of Ar spectra lines, we observed some spectra of C, CN, CH and C2. Through changing acetone content mixed in argon, we found that the optimum discharge condition for deposition can be characterized by the maximum concentration of carbonaceous species. The deposited film was characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. The XPS indicated that the film was mostly composed of C with trace amount of O and N elements. The FTIR suggested different carbon-containing bonds (−CHx, C=O, C=C, C-O-C) presented in the deposited film.

Polarization and Angular Distribution of Lℓ X-Ray Following Inner-Shell 2p3/2 Photoionization of Magnesium-Like Ions

The inner-shell 2p3/2 photoionization and the subsequent decay of Mg-like Fe14+, Cd36+, W62+ and U80+ ions are studied theoretically within the multiconfiguration Dirac—Fock method and the density matrix theory. Special attention is paid to exploring the influence of the non-dipole terms which arise from the multipole expansion of the electron-photon interaction in the photoionization process. The results show that the non-dipole contribution to the total cross section, the magnetic sublevels cross section of the photoionization process, the degree of linear polarization and angular distribution of the subsequent characteristic x-ray radiation become more important with the increase of photons energy and atomic nuclear Z. Especially for the cross section and the degree of linear polarization, the non-dipole contribution arrives at 50% for U80+ at four time energy threshold units. However, for the angular distribution, the maximum contribution does not exceed 4%, even for U80+ ions.

Energy-Crossing and Its Effect on Lifetime of the 4s24p 2P3/2 Level for Highly Charged Ga-Like Ions

The multi-configuration Dirac—Fock method is employed to calculate the energy levels and transition probabilities for the electric dipole allowed (E1) and forbidden (M1, E2) lines for the 4s24p, 4s4p2 and 4s24d configurations of highly charged Ga-like ions from Z = 68–95. The lifetimes of the 4s24p 2P3/2 level of the ground configuration are also derived. Based on our calculations, it is found that the energy level of the 4s24p 2P3/2 is higher than that of the 4s4p2 4P1/2 for the high-Z Ga-like ions with Z ≥ 74, so as to generate an energy crossing at Z = 74. The effect of the energy crossing is important to the calculation of the 4s24p 2P3/2 level lifetime for Ga-like ions with Z ≥ 74.

Atomic Structures and Radiative Properties of He-like Ions in Debye Plasmas

A detailed investigation of plasma screening effects on atomic structure and transition properties are presented for He-like ions embedded in dense plasma environment. Multi-configuration Dirac-Fock calculations were carried out for these ions by considering a Debye-Huckel potential. A large-scale relativistic configuration-interaction method is adopted to calculate transition energies and transition probabilities and to allow for a systematic improvement of the calculations. Comparison of the presently calculated results with others, when available, is made.

Fluorescence and Auger Decay Properties of the Core-Excited F-Like Ions from Ne to Kr

We systematically study the decay properties of the K-shell excited F-like ions with 10≤Z≤36 based on the multiconfiguration Dirac—Fock method. The Breit interaction, the QED corrections and the nuclear finite mass effects are also considered as perturbation. Auger transition rates, radiative, Auger and natural widths, as well as fluorescence and Auger yields for K-shell excited F-like ions are presented. It is shown by means of concrete figures that the decay properties change significantly with the increase of the atomic number Z; the Auger rate is overtaken at Z = 30 by the radiative decay rate. Several fitting formulae for the radiative and Auger widths and the fluorescence yields have been evaluated which is expected to be useful in plasma analysis and plasma modeling.

Relativistic Distorted-Wave Collision Strengths of Ni-, Cu- and Zn-like Au Ions

Excitation energies and electron impact excitation strengths from the ground states of Ni-, Cu- and Zn-like Au ions are calculated. The collision strengths are computed by a 213-levels expansion for the Ni- like Au ion, 405-levels expansion for the Cu-like Au ion and 229-levels expansion for the Zn-like Au ion. Configuration interactions are taken into account for all levels included. The target state wavefunctions are calculated by using the Grasp92 code. The continuum orbits are computed in the distorted-wave approximation, in which the direct and exchange potentials among all the electrons are included. Excellent agreement is found when the results are compared with previous calculations and recent measurements.