Electron-impact ionization of Ne⁷⁺

Abstract

We present a theoretical study of electron-impact single ionization of Ne7+(1s22s 2S) using a formulation in which the incident/scattered electron is described by distorted waves, while the final continuum states of Ne7+ are calculated by the R-matrix method, thereby incorporating the excitation-autoionization process. With nine states of the residual Ne8+ included, we have calculated single-differential and total cross sections for impact energies from the threshold energy at 8.8-80 au. The single-differential cross sections exhibit considerable structure due to autoionizing resonances, dominated by the 1s2ℓ2ℓ' states. Our calculated total cross section is in good agreement with the available experimental data and with theoretical values obtained by a close-coupling calculation. Total cross sections for ionization in which the Ne8+ is left in the 1s2s 1,3S or 1s2p 1,3Po excited states are also presented.

Calculations of electron-impact single-ionization cross sections of helium isoelectronic systems

“…The use of d 1 = 0.0 and d 2 = 0.05 for the two parameters in Eq. (11), obtained for the molecules in Ref. [29], seems valid for He.…”

“…The void in the experimental cross sections has to be filled in through generation of high-quality data by accurate theoretical methods. With the advent of fast computers, several quantal methods have been developed [1][2][3][4][5][6][7][8][9][10][11]. However, quantum calculations are arduous and become expensive even with the use of supercomputers.…”

Modified binary encounter Bethe model for electron-impact ionization

“…With the advance of quantum mechanical computational methods, some very accurate ab initio calculations were performed. Nevertheless, these calculations are very time-consuming, limiting the domain of applicability of such models [62,53,6,7].…”

Electron-impact ionization cross section calculations for lithium-like ions

“…[7,8] Although much work has been devoted to improving the theory of electron-impact ionization, there are still discrepancies between theoretical predictions and experimental data for some members of the sequence. [9,10] Therefore, it is of vital importance to investigate behavior of electron-impact ionization along the isoelectronic sequence.…”

“…Furthermore, the R-matrix method, which is independent of the energy of the scattered electrons in the inner region, was extended to the electron-impact ionization of Ne 7+ . [10] In recent years, the two-potential distorted-wave (TPDW) approximation, which uses different asymptotic charges for the distorting potential to study the mutual screening of the faster and slower electrons, has been developed and widely used in the calculation of electron-, positron-, and protonimpact ionizations of hydrogen-, helium-, and beryllium-like ions. [26][27][28][29][30][31][32][33][34] Compared with other theoretical and experimental data, generally more reliable results are obtained in these works.…”