This paper calculates the electron impact excitation rate coefficients from the ground term 2s22p2 3P to the excited terms of the 2s22p2, 2s2p3, 2s22p3s, 2s22p3p, and 2s22p3d configurations of N II. In the calculations, multiconfiguration Dirac-Fork wave functions have been applied to describe the target-ion states and relativistic distorted-wave calculation has been performed to generate fine-structure collision strengths. The collision strengths are then averaged over a Maxwellian distribution of electron velocities in order to generate the effective collision strengths. The calculated rate coefficients are compared with available experimental and theoretical data, and some good agreements are found for the outer shell electron excitations. But for the inner shell electron excitations there are still some differences between the present calculations and available experiments.
In this paper, we explored the characteristics of the interference effects betweenperturbative states in hyperfine induced 2s2p ~3P_0,~3p_2→2s^(21)S_0 transitions of Be-like ions. It wasfound that the interference effects non-monotonically change with increasing atomic number Zin these two transitions. The strongest interference effect is near Z= 9 for 2s2p^3P^0→ 2s^(21)S_0transition and near Z= 7 for the other.
In this work,the KLL dielectronic recombination (DR) processes of highly charged He-like to O-like xenon ions are studied systematically by using a DR program,which is based on the multi-configuration Dirac-Fock (MCDF) method.The KLL DR resonant energies and the corresponding resonant strengths are calculated,emphasizing especially the effect of the Breit interaction on the DR strengths.The theoretical KLL DR spectra are obtained and compared with the latest experimental results obtained in the Shanghai Electron Beam Ion Trap.
The multi-configuration Dirac-Fock(MCDF) method is implemented to study doubly excited 2s2p ^(1,3)P_1 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 1s^2 ~1S_0 state to the doubly excited 2s2p ^(1,3)P_1 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 ρ~2 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 ~3P_1 state.
In this paper, the capabilities of laser-induced breakdown spectroscopy (LIBS) forrapid analysis to multi-component plant axe illustrated using a 1064 nm laser focused onto thesurface of folium lycii. Based on homogeneous plasma assumption, nine of essential micronutrientsin folium lycii are identified. Using Saha equation and Boltzmann plot method electron densityand plasma temperature are obtained, and their relative concentration (Ca, Mg, Al, Si, Ti, Na,K, Li, and Sr) are obtained employing a semi-quantitative method.
