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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.

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.

The multi-configuration Dirac?Fock (MCDF) method is implemented to study doubly excited 2s2p 1,3P1 resonances of the helium atom and the interference between photoionization and photoexcitation autoionization processes. In order to reproduce the total photoionization sprectra, the excited energies from the ground 1s2 1S0 state to the doubly excited 2s2p 1,3P1 states and the relevant Auger decay rates and widths are calculated in detail. Furthermore, the interference profile determined by the so-called Fano parameters q and p2 is also reproduced. Good agreement is found between the present results and other available theoretical and experimental results. This indeed shows a promising way to investigate the Fano resonances in photoionization of atoms within the MCDF scheme, although there are some discrepancies in the present calculations of the 2s2p 3P1 state.

This paper calculates the transition wavelengths and probabilities of the two-electron and one-photon (TEOP) transition from the (3s1/2-1 4dj) J = 1,2 to (3p3/2-1 4s1/2)J = 1 and the (3p1/2-1 4s1/2) J = 1 to (3dj-1 4dj')J = 1,2 for highly charged Ni-like ions with atomic number Z in the range 47 ≤ Z ≤ 92. In the calculations, the multi-configuration Dirac–Fock method and corresponding program packages GRASP92 and REOS99 were used, and the relativistic effects, correlation effects and relaxation effects were considered systematically. It is found that the TEOP transitions are very sensitive to the correlation of electrons, and the probabilities will be enhanced sharply in some special Z regions along the isoelectronic sequence. The present TEOP transition wavelengths are compared with the available data from some previous publications, good agreement is obtained.

In a recent XUV photoabsorption spectrum of Cs III ions by Cummings and O'Sullivan [2001 J. Phys. B 34 199], rather large linewidths were found for the 4d95s25p6 – 4d105s25p5 transition which are quite in disagreement with corresponding quasi-relativistic multiconfiguration Hartree–Fock (MCHF) calculation. In the present work, a detailed multiconfiguration Dirac-Fock study has been carried out to explore this discrepancy. Owing to the detailed consideration of electron correlation effects, some 'forbidden' Auger decay channels, such as 4d105s25p35d and 4d105s05p6, would become 'open'. As a result, remarkable improvement of the linewidths has been obtained in our calculation. Furthermore, the theoretical Auger spectrum of the 4d95s25p6 core-excited states of Cs III ions is given in the present work.

The photo-excitation and Auger decay processes of inner-shell double vacancy states 1s2s2p6(1,3S)3s3p of neutral neon atoms have been studied theoretically. Multi-configuration Dirac-Fock (MCDF) calculations have been carried out, with electron correlation effects taken into consideration. The relaxation of core and excited orbitals and configuration interaction are found to be crucial to creating the double vacancy states by single photo-absorption. The predominant decay paths for the double vacancy states turn out to be of the LLM Auger decay to 1s 2s22p53s(3p), KLL Auger decay to 1s22s2p43s3p, and KLM Auger decay to 1s22p63s(3p). They lead to further Auger decay, creating the neon ions of multiple charge states. For both double and single vacancy states the spectator type of Auger process is dominated in all the Auger decay processes. Theoretical Auger electron spectra are presented for further investigations, experimental and theoretical.

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.

Based on the Dirac–Fork–Slater method combined with the multichannel quantum defect theory, the recombination processes of electrons into bare uranium ions (U92+) are investigated in the relative energy range close to zero, and the x-ray spectrum emitted in the direct radiative recombination and cascades processes are simulated. Compared with the recent measurement, it is found that the rate enhancement comes from the additional populations on high Rydberg states. These additional populations may be produced by other recombination mechanisms, such as the external electric-magnetic effects and the many-body correlation effects, which still remains an open problem.

In the framework of multi-configuration Dirac–Fock theory, a detailed calculation is performed for the decay rates and the energies of the doubly excited 2s2 1S0 state of He-like ions, of which atomic number Z ranges from 6 to 92. The 2s2 1S0 – 1s2S1/2 Auger decay is predominant at low Z regime, whereas the 2s2 1S0 – 1s2p 1,3P1 two-electron one-photon transitions become quite important in moderate and high Z regimes. For heavy ions with Z≥72, the contribution of 2s2 1S0 – 1s2s3S1 M1 transition is significant. The Breit interaction considerably enhances the 2s2 1S0 – 1s2S1/2 Auger rate at high Z regime.

Transition probabilities of the 2s2p3 5S2-2s22p2 3P1,2 intercombination transitions in NII have been calculated by using a large-scale multiconfiguration Dirac-Fock method. In the calculation the most important effects of relativity, correlation and relaxation are considered. From the calculated transition probabilities, the lifetime of the 2s2p3 5S2 metastable state is derived. The result is in excellent agreement with the latest experimental result. In the meantime the influence of anomalously strong relaxation effects on probabilities of the 2s2p3 5S2-2s22p2 3P1,2 lines in NII have been found.

The cross sections of the Is electron photoionization and corresponding shake-up processes for Li atoms in the ground state Is2 2s and excited states 1s2 2p, 1s2 3s, 1s2 3p and 1s2 3d are calculated using the multi-configuration Dirac-Fock method. The latest experimental photoelectron spectrum at hv = 100 eV [Cubaynes D et al. Phys. Rev. Lett. 99 (2007) 213004] has been reproduced by the present theoretical investigation excellently. The relative intensity of the shake-up satellites shows that the effects of correlation and relaxation become more important for the higher excited states of the lithium atom, which are explained very well by the spatial overlap of the initial and final state wavefunctions. In addition, strong dependence of the cross section on the atomic orbitals of the valence electrons are found, especially near the threshold.

Based on the multi-configuration Dirac–Fock method, theoretical calculations are carried out for the dielectronic recombination (DR) rate coefficients and the collision excitation rate coefficients of Sn10+ ions. It is found that the total DR rate coefficient has its maximum value between 10 eV and 100 eV and is greater than either the radiative recombination or three-body recombination rate coefficients (the number of free electrons per unit is 1021 cm3) for the case of Te > 1 eV. Therefore, DR can strongly influence the ionization balance of laser produced multi-charged tin ions. The related dielectronic satellite cannot be ignored at low temperature Te < 5 eV.

On the basis of successfully predicting low-lying energy levels for the element fermium (Z = 100), we calculate the resonance energies, absorption oscillator strengths and the first ionization potential of the element hassium (Z = 108) by taking important relativistic and improved electron correlation effects into account using the multiconfiguration Dirac–Fock method. These calculations are carried out with the aim of assisting experimental investigations of hassium.

In the frame of quantum defect theory, the resonance excitation cross sections of 1s - 2s electron-impact excitation of He+ ion are calculated by a simple relativistic configuration interaction method. The present theoretical results are in agreement with the previous experimental measurements.

The transition energies and electric dipole (E1) transition rates of the K, L, and M lines in neutral Np have been theoretically determined from the MultiConfiguration Dirac—Fock (MCDF) method. In the calculations, the contributions from Breit interaction and quantum electrodynamics (QED) effects (vacuum polarization and self-energy), as well as nuclear finite mass and volume effects, are taken into account. The calculated transition energies and rates are found to be in good agreement with other experimental and theoretical results. The accuracy of the results is estimated and discussed. Furthermore, we calculated the transition energies of the same lines radiating from the decaying transitions of the K-, L-, and M-shell hole states of Np ions with the charge states Np1+ to Np6+ for the first time. We found that for a specific line, the corresponding transition energies relating to all the Np ions are almost the same; it means the outermost electrons have a very small influence on the inner-shell transition processes.

The angular distribution and polarization of the x-ray photoemission of highly charged helium-like ions is studied following the K—LL dielectronic recombination of initially hydrogen-like ions. Calculation is carried out within the framework of the density matrix theory combined with the multiconfiguration Dirac—Fock approach. Attention is paid to magnetic sublevel alignment in the resonant intermediate state and to its nonuniform radiative decay processes. It is shown that the Breit interaction between the incident and target electrons plays a significant role for the alignment of the resonant state and thus causes a substantial change in the x-ray emission characteristic, when compared to the incorporation of only the (non-relativistic) Coulomb interaction. The most prominent difference in alignment parameter is found in the 2s2p1/2 J = 1 resonant state for a wide range of atomic numbers from 9 to 92. For this resonant state of helium-like ions, the Breit interaction becomes significant for ions with nuclear charge Z ~ 30 already.