Study On Electron Collisions With Atomic Ions And Photoionization Of Atoms Using R-matrix Method

Electron impact excitation of atomic ions and photoionization of atoms have been studied. The following is the main contents of the present paper:1. Electron collision strengths for 1s-2s and 1s-2p transitions of hydrogen-like He+, Li2+ ions have been calculated using closed-coupling R-matrix method. Our results shows that calculations should include, at least, ten target states, which can give accurate data for electron collision strengths for excitation of n=2 states from ground state of hydrogen-like ions. We can inferred from the calculations, with the increase of Z, the energy for electron impact excitation with hydrogen-like ions will also increased, but collision strengths will decreased.2. Using R-matrix method the photoionization cross sections of ground state of atomic nitrogen are calculated for photon energies between 1 and 3 Ry. The total cross section we calculated lie about 20% higher than those of experiments from threshold to 1.7Ry, the discrepancy maybe lie in the use of inaccurate discrete oscillator strengths in the experiment to normalize their relative datas. Excellent agreement is found between we calculated energies of autoionization resonances 2s2p3(5S°)np(4Pe)(n=3 -10) and experimental results.3. The partial and total photoionization cross sections of fluorine are calculated using R-matrix method for photon energies between the 3P and 1D thresholds. We analysed the autoionization resonances 2P4(1D)ns 2D, 2P4(1D)md 2P and 2P4(1D)md 2D, and present energy positions are in good agreement with the experiment.