Electron-impact ionization of

Abstract

We have calculated total and single differential cross sections for electron impact ionization of using a method that combines the distorted-wave Born approximation for the incident/scattered electron with an R-matrix treatment of the system. Our calculation included eight states of the final ion, namely , and six states with the configuration , and up to the -pole component of the interaction between the ionizing electron and the target. The single differential cross sections exhibit considerable structure due to autoionizing resonances, including a large resonance due to the quasi-bound state . In the calculation of the total cross section, a modification to the usual half-range approximation is proposed, which ensures that the contributions from autoionizing resonances have the correct thresholds. Our theoretical results for the total cross section are in good agreement with the experimental results.

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

“…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.…”

Electron impact ionization in K‐, L‐, and M‐shells of atomic targets

“… Same as in Figure 1 for the total EIICS with ionization in the 1s and 2s orbits for the Li‐like ions: (a) Be + , (b) B 2+ , (c) N 4+ , (d) O 5+ , (e) Ne 7+ , and (f) U 89+ . The open circles in (a)–(d) are the CCC results of 73 and those for (e) and (f) are the calculations from DWBARM of 74 and RDWBA of 71, respectively. …”

“…The dotted lines are the DWBX predictions of 72. The open circles in (b) are from DWBARM of 74; in (c), the RDWBA results of 71; and in (d) and (e), the CBA calculations of 76.…”

“…To augment the comparative study of performance, we also display the available results from quantum mechanical theories like distorted wave Born approximation (DWBA) 67–69, relativistic DWBA (RDWBA) 70, 71, distorted wave Born‐exchange approximation (DWBX) 72, convergent‐close coupling approximation (CCC) 73, DWBA with R‐matrix (DWBARM) 74, Coulomb‐Born approximation (CB) 75, and CB with autoionization (CBA) 76. The DWBA results of 67 for Li + , B 3+ , C 4+ , N 5+ , and O 6+ , and those for U 90+ from RDWBA of 70 are shown in dotted lines of Figure 1.…”

“…The DWBA results of 67 for Li + , B 3+ , C 4+ , N 5+ , and O 6+ , and those for U 90+ from RDWBA of 70 are shown in dotted lines of Figure 1. The predicted EIICS from CCC 73 for Be + , B 2+ , N 4+ , and O 5+ ; those from DWBARM 74 for Ne 7+ and from RDWBA 71 for U 89+ are displayed in open circles of Figure 2. The calculated EIICS for C 2+ from DWBX 72 are given in dotted line of Figure 3.…”